That's good news on the Microvision carts. I think part of the reason that there weren't many wrong bits found is that I play-tested the games in Paul's emulator, which uncovered many of the errors. But some of the games are pretty difficult to figure out, and some of them seem to have odd quirks even playing on an original unit, so it's good to have another pair of eyes checking them out.
As for Speak and Spell stuff, I don't think I've got anything else that's undumped. Let me know if there's anything in particular you're looking for.
I tried for a couple of Dark Towers on Sunday. One game with a broken tower went for something like $70 shipped, which is more than I'm willing to pay. Another auction was just for a broken tower, so I figured I could get that, but it went for over $50 shipped.