I printed one, but I can't use it because the mounting grooves don't match with the E3D.

Yeah, I did say it made for the original hot end, but if you want to give me dimensions of the E3D hot end, I could try to make a version for that one.

I would need the diameter, of the fins, as well as of the main tube, fins spacing, thickness, etc.

I bought a used hot end from one of our members that upgrade to an e3D hot end adn fitted it on the extruder.  At the same time I added the bearing and pressure spring.

I'm not quite ready to do the swap with the original print head yet though.

I noticed there have been a few downloads of the model.  Has anyone else printed this yet? How did it work out for you?

Edit:
Updated image

Wow, really?  Thats so stupid..

I know what I'm not going to buy ever..  I'm sitting on an education license of autodesk from my highschool and I know I'm not going to ever renew it now.

So how's solidworks? lol

I learned Solidworks on my own.  I'm no wiz at it by any means, but for what I need to do, I manage.  I've been using it for the last couple of years, and I do mostly mechanical design concepts.

As I mentioned, I work for a computer manufacturer, and periodically I have to design various components and accessories.  Since most prototype and design house in this line of work use Solidworks, the company got a copy for me to use.

Previously I was using pencil and paper, or doing roughs with SketchUp, but that app has some serious limitations.  Solidworks took a little getting used to, but once you get the basics, it's fairly easy to use.  Besides there are thousands of pre-made parts and basic hardware available in the library that make one's work easier.

The models and exported STLs are usually pretty clean and don't require a lot (if any) massaging or repair.  In short, I do like working with it.

I know what I'm not going to buy ever..  I'm sitting on an education license of autodesk from my highschool and I know I'm not going to ever renew it now.

So how's solidworks? lol

Thanks! Hopefully will be able to apply tweaks/redesign with a legup by using your STP files. In the past I've been able to import reasonably well from Step. 

You solidworks people, insisting on using the buggier software out of legacy . [Just kidding, but I'm an ardent supporter of autodesk. Probably because I had to learn solidworks in class via a ridiculous and boring lecture format, versus learning autodesk through project working and online tutorials.] Also because autodesk supports many nifty DIY efforts, and software too sometimes (like meshmixer 2.0).

I for one am not a fan of Autodesk.  I used to be a draftsman in a previous life, and Autocad was my bread and butter.  Then I got into computers, but a few years back, I won a copy of 3D Studio at a trade show, for which I had no use, so I tried to sell it.  eBay pulled the listing at the request of the AutoDesk lawyers.

I called them (Autodesk) and according to them you cannot resell any Autodesk products, regardless of whether they've been registered or still in shrinkwrap.  Once you bought them they're yours, "didn't I read the EULA?".  I told them that the package was sealed, therefore I had no access to the EULA, so they said they didn't care.

So what can I do with a $2000 modelling package if I'm not a modeler?  "Give it away, learn to use it, throw it away, return it where I got it, we don't care as long as you don't try to sell it.  Oh, and If I try to relist it, I could get banned from eBay.

Needless to say, I was really pissed.  I was sitting on something of value that I couldn't do anything with, because of their greed and desire to make money by making sure everyone buys a retail copy. 

Ever since them, If I get a chance to heckle those idiots in public (trade shows, etc), I do.

You solidworks people, insisting on using the buggier software out of legacy . [Just kidding, but I'm an ardent supporter of autodesk. Probably because I had to learn solidworks in class via a ridiculous and boring lecture format, versus learning autodesk through project working and online tutorials.] Also because autodesk supports many nifty DIY efforts, and software too sometimes (like meshmixer 2.0).

Can you post STP files?  I'd like to try this, since the fit of the MK5 on my E3D has become loose somehow.  I have a new stepper for the extruder that is a little longer than the stock one, so I'd like to extend the back of the platform a little.

NO problem, what version , AP203 or AP214, does it make any difference?

AS for extending the back, I'm not sure you can go much further, In my case, I have a ball screw nut that is pretty big, and it barely clears it right now, but I'm sure you can figure it out for your particular machine.

Edit: 
Here are the 2 versions of the extruder in STEP format (AP214).  I imported them back into Solidworks, and they appear to be complete.

Let me know if you have any problems with them.

I like the bracket at the back, and the wire guide.  How short does the bolt need to be that holds the fixed end of the belt to keep it from running into the bearing on the inside, while not sticking up on the outside and getting in the way of the bolt that holds the adjustable end of the belt?

The bolt length (threaded part) should not exceed 6mm.  To clear the adjustable bolt, I would use either a countersunk flat head or a pan/truss heat type with a a very shallow profile.  Total available space is 2mm, which includes the belt thickness.

For those that want to print this or tinker with it, I'm adding the STL files for both versions V3 and V4.  Each STL has all the parts in a layout intended to be printed on the SD3.  You can also use NetFabb to separate and save the individual parts.

In terms of hardware, you'll need the following:

Original motor, heatsink & fan
original hot end
Original pressure bearing + adjustment nut, washers & spring
1x LM8UU bearing for the rear
2x LM8UU bearings for front, or alternately 1x LM8LUU (long)
2x M3 x 25mm (lower extruder frame top bolts)
1x M3 x 20mm (lower extruder frame lower left bolt)
1x M3 x 20mm (pressure bearing arm bolt)
1x M3 x 14mm (upper left corner extruder frame bolt)
2x M3 x 12mm (horizontal support plate front bolts)
1x M3 x 15mm + sprig (horizontal support plate rear bolt)
1x M3 x 25mm (pressure arm adjustment screw - embedded in lower right of extruder frame)
2x pieces 4mm(OD)x2mm(ID) PTFE tubing cut to size for filament guide

Feel free to ask questions.

Here is a variation of the horizontal platform/base plate. 

It has lateral support that holds the back end of the motor/fan assembly from wagging back and forth and applying torsional stress to the front mounting plate.  The left side also has a cable routing guide.

Here is yet another variation, and probably closer to what Ian Johnson had in mind. 

This one bolts to the bottom of the fan, and the back of the support platform.  It has 2 slotted holes to allow about 3mm worth of adjustment for possible variations in the fan and heatsink depth.