UPDATE: A New updated version of MendelMax is available at http://www.thingiverse.com/thing:20355. It is recommended for all new builds.
MendelMax is a new RepRap 3d printer designed by Maxbots. It is a true reprap, using printed brackets, but instead of using threaded rod for the structural elements it uses inexpensive aluminum extrusions. This gives a huge increase in rigidity for a minimal extra cost (Self sourcing will cost about $50 more than a standard Prusa when purchased from the recommended suppliers). The required extrusions are available world wide from a variety of suppliers.
In addition to greatly increased rigidity, this design is faster to assemble (probably 4 hours for most users), easier to print, has a larger build volume (~215x235x190 if built at the standard dimensions), and is easier to hack on.
Update 2/7/2012: MendelMax full kits and hardware only kits are now available from Maxbots (aka Kludgineer on Thingiverse) @ http://store.mendelmax.com!
For full assembly instructions and parts lists, see http://www.mendelmax.com.
The X & Y axes are standard Prusa parts, so any design can be used.
I finally got an STP file uploaded. Please let me know if you have any issues with that file.
The SCAD conversion is mostly complete and available at https://github.com/maxbots/MendelMax
To learn how to execute scripts in FreeCAD, read the tutorial at: http://mendelmax.com/tikiwiki/tiki-index.php?page=Getting+Started+with+FreeCAD+scripting
Note there may be minor incompatibilities between SCAD generated parts and the parts here on Thingiverse. It should not be an issue intermixing to some extent, but parts that directly connect to another (for example the Y & Z rod mounts & clasps) should always come from the same source.
Also note that the SCAD parts are untested at this point so I recommend only using them if you already have a working printer to reprint any parts that may need tweaking.
Y motor mount & Y Idler mount replaced with much more robust designs. These should fix any flexing issues you might have.
The part "Lower Vertex Cupcake" is a replacement for the standard Lower Vertex, but is reduced in height slightly to allow printing on the Cupcake and other small-format printers. Either part will work, but you only need to print one or the other, don't print both.
New, improved Lower Vertex pieces uploaded. These parts should be easier to print, easier to assemble, and better looking, though that comes at the expense of being somewhat slower to print.
The new parts need to be printed in mirrored pairs, so the the included STLs include one of each part. Print two copies of each of the parts (lower vertex lower and lower vertex upper). You will end up with 8 parts total. If you prefer, you can get the individual STLs for each of the four different parts in the individual lower vertex zip file.
One important not about these new parts: WHile they are just as rigid as the old parts, they are not as storng as the old ones. They are amply strong to use the MendelMax as a printer, but DO NOT STAND ON IT!
The original parts are still here if you prefer them.