Modified versions of Tony's right-side Y belt holders (part 10030, wiki.bitsfrombytes.com/index.php?title=Spare_parts#Part:_10030) for the RapMan. Mine is a RapMan 3.1; install these on earlier versions at your own risk... might work, might not.
I've designed and included left Y-belt holder also, parts 10026 and 10036. These have the protrusions to hold the X limit switch and the extruder conduit.
Changes to original holders (also included in new parts):
Bolt hole edges have been redesigned to help clear the 8mm rod cutout. There should now be less filing needed (previously, skeinforge would on some settings actually build material into the 8mm rod cutout, which would then have to be removed).
Slots have been removed and replaced with holes, because they weren't working very well for their intended purpose and just added extra fussiness when tightening the belt..
Nut rebates have been added. They are slightly deeper than standard nut rebates, so the nut will still be captivated when the belt tensioner is loosened.
Update 2011-11-21: Y left back clamp tweaked and reuploaded because my belt was looking crooked. Turns out my pulley was out of place and that was most of the problem, but I did move the belt clamp inward (+X) by about a millimeter.