OK... This is a longer answer than you may want.
1) Yes, this is slower than pfSense forums.
Not sure why. I think it is because m0n0wall is very stable, and does not change as much.
2) Size... Sure this can be done. It is NOT trivial. Part of the "drive space" is space for future image upgrades. You could remove that functionality, and shrink the image. You would need a full development environment. Instructions are here.
http://svn.m0n0.ch/wall/branches/freebsd8/build/scripts/README3) 1.2 is a good image. It was quite stable. It still has some issues with captive portal that were not worked out, and a few other addins. IPv6 is right out. But it is secure.
So, that replacement dom is looking pretty good, huh?