There is a realforce in the
classifieds section for $200.
It was still for sale when I asked a couple days ago. I can't believe it lasted even that long though, as that's actually a pretty damn nice price for that keyboard. If I wasn't already (way) over budget, I would definitely pick it up myself.
Then again, you could also look into the Unicomp keyboards, if you are interested in buckling springs (my preferred switch), or look to snag an Apple Extended Keyboard II from ebay, if you want to try an Alps switch.
I also spend a lot of time on my keyboards, writing code (about comparable). If you're a UNIX guy, definitely take a look at the HHKB, for layout, rather than size. Unicomp can make a PS/2 Customizer with that layout for a small upcharge. Total would still be under $100, even with their recent price increases, I would expect (mine was under $90).
You could also see if a bolt modded model M comes around on the classifieds, as well. As I told a friend of mine, they make you a better coder :-P.