A weird idea just occurred to me (what can I say; tis the wee hours) which
I'm almost positive is completely ridiculous, but I figured I'd bring it up
here because, well, the lot of ye are the only people I can think of
offhand who might know.  :)

I have a IIcx here, with the pokey 16MHz 030 (runs NetBSD a hell of a lot
more efficiently than MacOS, of course). I was wondering if anyone
thinks it might be possible to rip out the 16MHz chip (it's probably
soldered in, but that's another story) and replace it with another 030, say
a 25MHz or 33 or something.

As I said, I'm sure there are a *thousand* reasons why this could *never* 
work and is an incredibly silly notion to begin with, but...if anyone can
tell me, I'd be interested to know why.  I'm guessing any number of things
involving clock speed, bus speed, etc.  But on the other hand, I'm thinking
the pinouts and instruction sets for two 030's of different speeds have
gotta be exactly the same...