I considered SuperCard, but there are some things (such as shared fields) that were simply not ported over, which then may break functionality.

As for performance, my Mac LC 575 seems to go along satisfactorily, and it's only an 68LC040. I have not had a chance to test it on my IIsi, simply because I can't get video out of it (btw, can anyone help me with that? I know it's a working computer - I just can't get any monitors to sync to it.)