go to a tire store and ask them if they would rub w/ adapters....
there are special companies that make rim adapters for just about anything i.e. going from chevy custom rims maybe to fit a ford ( but ive never owned a fwd so u will ahve to check for yourself )
I have never seen an adapter that adds positive offset and that's what would be needed to get most RWD rims to work properly on a FWD car. Most [OEM] RWD car rims are close to zero offset. [There are specialty aftermarket "deep dish" rims with extreme negative offset but most are close to zero.] FWD have various amounts of offset but it's almost always a significant positve amount. http://www.tirerack.com/wheels/tech/techpage.jsp?techid=101
The other way (FWD rim on a RWD) is possible because the adapter is also a spacer and therefore adds negative offset to the positve offset of the FWD rim to get it closer to zero for the RWD car.