The vanilla A1200 barely has enough spare juice to supply a 68030 card and some RAM at a stretch, possibly with a notebook 2.5" HDD attached. Considering I blew my PSU after fitting a 68040 and a 16mb SIMM, not to mention a 3.5" HDD then the demands of a Voodoo (which is exponentially more powerful than the 68030 the A1200 was originally designed to take), plus the issues of cooling such a setup in the A1200's cramped case means powerful fans, which need more power... You get the picture.
The safest option is to take the A1200 and rehouse it with an AT PSU with sufficient juice to drive everything and the extra space to circulate cooling air.
Mind you, it would be nice to be able to fit a decently powerful machine into an A1200 sized case...