I can't find old MESS binaries, even googling.

This page

http://www.mamedev.org/oldrel.html

has only MAME versions.

BTW, I've taken a look at the debugger, and c65 driver starts executing from 0x0000 a series of brk instructions (this with MESS 0.149). Is that normal?

I would try to debug with MESS 0.135, if only I could find it.