Spare tire, space saver donut options?

Any body out there tried using a later model space saver spare wheel set up in their A-body? I'm switching to 4.5" bolt pattern and rather than looking for a correct spare thought a cheap modern spare would also take less space, and weigh less, and sometimes people just throw them out down here too. I know the spare from my wife's Mazda fits, but are there any other options?