There is a port for Redneck Rampage here:
http://code.google.com/p/erampage/downloads/list
Enjoy!

Some russian team worked on making Redneck Rampage runnable with EDuke32, but it's terribly buggy.

Like it's been said before, the source code to Redneck Rampage hasnt been released, and probably won't since it's probably lost, that's why there hasnt been a windows port of Redneck Rampage.

What about this thing.
http://www.proasm.com/
Now click on the leonard head and it gives you a thing called rrsetup that gives a startup window for redneck rampage and runs on a modified version of dosbox.

From what I can tell, that functions more like a DOSBox frontend than a true port.

Yep, it's just a frontend that sends commands to dosbox.