I wouldn't have thought it would be possible unless the game booted from a normal Workbench-formatted disk. Didn't most early games use their own boot loaders or something? (I know that a lot of disks couldn't be read through Workbench.)
It should be possible to create a bootable Workbench CD AFAIK, then you could put some WHDLoad installations on there and load A500 games that way.
