There are tons of programs that support ReWire, including those not made by Propellerheads (the guys who make Reason). I Rewire Reason through Cubase all the time so I can use Reason's synths and still be able to handle VSTs and manipulate audio with Cubase. It's a great tool.

Here's a few... Ableton Live, Cubase, Torq, Sony Acid Pro, Renoise, ProTools, Fruity Loops, there's a more complete list (and more info) here:

http://en.wikipedia.org/wiki/ReWire