Most big manufacturers' forks are very hard to maintain after they are ~3 yrs old due to lack of spare parts support. THe simple RST fork is more likely repairable than any of the ones you listed should they ever fail. Since it doesn't work now, try to tear the RST down and see if you can't make it work. You have nothing to lose.

However, if you look online you can find new forks from last year for ~$100 - $200.

Edit: For example (although this one is not available, I didn't look that hard.) http://www.bikeman.com/FK8702.html