I have just discovered a cross-platform Java library that supports all the 
Lego Mindstorms RCX versions (including the USB towers!) under multiple OS 
platforms. 

http://www.escape.com/~dario/java/rcx/

I think that using this library to make an server program that Squeak could 
communicate with would be the easiest way to make cross-platform support for 
Mindstorms RCX units.

Know any Java programmers who could make a program using this?

My idea is to find someone to do this:

Make a command-line Java application that will act as a server for RCX control 
and communications, letting one (or more) clients connect via TCP sockets.

Then one or more Squeak images could connect to this "RCX server" over the net 
and talk to the Lego Mindstorms RCX brick(s) attached to that server machine.

This would be much easier than re-implementing all that stuff in Squeak.

-- 
Ned Konz
http://bike-nomad.com/squeak/