Here you can find todays (06/29/2008) CVS build1) of DOSBox 0.72. It is an universal binary that runs on G4,G5 and i386 based Macintoshes under OS X 10.5 (and up).
I used the following extra libraries and linked them static using GCC 4.0.1 from Apple and -march=pentium-m -mtune=pentium-m -msse3 as opt-level.
Unfortunately I have quite some trouble with this build (it really crashes a lot) on INTeL - it looks a bit more stable on PowerPC, though.
UPDATE:
I did a new CVS build last weekend. It is still unstable and crashes with certain apps. But if you need to have the bleeding edge CVS version this one is the right choice. Ah .. yes.. its universal (runs on PowerPC and INTeL) and is for Leopard only.