I made these replacement horses
The dimensions are generally the same as the existing ones so that they don't interfere with each other, just not as thick.
Replicator 2, MakerWare, Miracle Grue
added http://www.thingiverse.com/thing:38272 to the ends to reduce curling (really helps)
20%infill, 2 shells
.20 layer thickness
default temp and speed (230C and 80mm/s)
I printed two at a time to save time in case both turned out well, but not more than two in case something failed and would waste the whole thing.