Given how long my Power Mac 9500/180 takes to just "make clean" on
pkgsrc (more than 24 hours), I'd say you'd probably have more luck
crosscompiling. It's less a function of the computers being slower
than we remembered than it is one of the compilers and other
userland having grown large enough to fit modern desktop machines
in the past few years. I'm finding the macppc port to be almost
unusably slow on 604e machines, which definitely wasn't the case a
few years ago. On a 68040, I think you're probably looking at
a big problem. :-)
That said, one of my pet "back burner" projects is to make a cheap
rackmount case for LC motherboards (all the "pizza-box" style ones
have the same basic outline, so it should work for all of them),
since they make OK DNS/mail servers. If anyone knows a good way
to do that, let me know (Protocase is nice for a lot of projects,
but sadly not this one because it's not super-cheap and doesn't
do bends the way I'd need). I know someone did something similar
for original iMac motherboards a long time ago (Marathon Computing
or something similar?).