If you can get b25 running, it goes up to 50 files at a time and 50 streams per
file at a time, but is still limited to 50 download connections total. On a typical
DSL or cable connection you'll typically hover at around 35-50 connections at
a time but the lack of artificially imposed limits does eliminate the loss of
opportunities to connect to fast sources.
BearShare Pro is almost as good but the limit of streams per file is much lower.