FWIW, I've previously done simple benchmarks of Comanche doing bulk
downloads, and found it just as fast as Apache and scp: ie, it saturates
the network.  This was on 10Mbit/sec networks.

For simply filling up a T1 link, Squeak and Comanche should be fine.  I
don't know what was different about my old computer, from the machine
you are testing on, but clearly something funny is going on.  Sorry I
don't have any specific suggestions, but maybe this at least gives you
some hope!

-Lex