well, since I didn't find one, I built one..

http://camlaw.rutgers.edu/~tomryan/rdesktop.dmg

simple installer will place rdesktop in /usr/bin on your mac

rdesktop is from the latest sources on the site (1.6.0) and is a universal binary compiled against a static universal libcrypto.a from the latest openssl sources (openssl-0.9.8l) and should work with 10.4 on.

I hope that someone finds this useful.

Tom