Not gonna try it (neverevernever), but UAE only emulates a CS-PPC on the HW (you'll need to download the flash-ROM from some questionable sites) therefore the limitation to 128MB (OS4 does not see Z3-RAM).

OS4-P96 still supports 68k drivers, allowing the UAEGFX one to run (so no 3D). Asssigning a separate Voodoo,Permedia or Radeon to UAE does not work.

All in all, a little less useless compared to running it on real HW in some aspects, completly useless in everything else.