Treo 680
 

It appears the 680 will work fine with the Bluetooth Assist package. Apparently it transfers the contacts you have in your favorites as well as any contacts on your SIM card, but not the contacts from your regular address book. This was posted over at the treocentral forum.

I ordered mine today. They are $399 unlocked with free shipping and a free 1 GB memory card from the Palm store. :)

Well, I got my Treo today. I didn't get a chance to pair it with the X5 yet, but so far I am very impressed with the phone. The main criticism of this phone is that it doesn't have 3g and only uses EDGE. Well, I can say for sure that this is definately the fastest EDGE phone I've used. Web pages load extremely quick -- I'd say quicker than some of the EVDO Verizon phones that I've used like the Motorola Q. I'll report back in a few days to advise on the results of pairing with the X5. :)