Here are set of STL files for Prusa i3 design published by Twelvepro.com
IMPORTANT: With "improved laser cut frame", you can really, trully use all of the original Prusa i3 parts designed by Joseph Prusa and posted on github.
You don't need four parts for Z Axis because they are redundant and implemented with laser cut parts.
About posted files and how their differ from Prusa's design:
1. All clamping parts designed for GT2 2mm belts only.
2. X Idler uses M5 Screw to hold two 625ZZ Ball bearings. Original i3 used one M4 mounted bearing and printed idler.
3. Y Idler also uses M5 Screw to hold two 625ZZ. Original i3 used one M4 mounted bearing and printed idler.
4. X Motor Part has adustment screw to fine tune level of Z against Z end stop switch.
5. Y Corners have side cutouts for better wrapping of tie wrap around y shafts.
6. Y Belt Clamp has 0.9mm of clearance for belt which provides enough clamping and still you can pull belt trough it with pliers.
7. Y Motor - changes are purely cosmetical.
8. Y Bushing holders - better grip of LM8UU, also they look better to me.
Only STLs are here. Printer posted by Twelvepro thingiverse.com/thing:39889
He will repost these files, DXFs as well as BOMs, eventually.