Well, I decided to take the chance on ebay and get myself a passport 8500 x50.
I got it for $150, which I don't think is too bad, its an 8500 x50, Rev 5.
I've had it for a few days now and it seems to be working fine. So I am pretty happy with the purchase so far.
My friend has a regular (not x50) 8500 and we did a little testing to make sure mine is working properly and it seems to be.
I wired it right above the RVM, I used the cig lighter cord and a coupler and ran some phone cord up to the RVM location and it works great, I'll probably get the hardwire kit at some point.