Besides.. Its scarileige. If it can't be done with a stock 68000, it doesnt need to be done on an A500.. Leave it alone..
Do some worthwhile upgrades like:
2megs chipram
ECS denise,
REAL FASTRAM.. (get rid of any ram thats in the trap door, that isnt CHIP ram)
A 68010 will not cause any compatability/stability problems, as long as you dont go jacking with the clock-speed. Leave it at the stock 7.14mhz and it will work fine.. Theres really a negligable-to-zero performance advantage, but hey.. If you've got one floating around, theres no harm in dropping it in..