I wonder the same thing. There's been lots of discussion of USB tethering, and the hotspot, but I wonder whether it's possible to tether via Bluetooth Dial-Up-Networking? Does the Amaze support that particular Bluetooth profile?
If so, does tethering that way invoke the TMobile upsell screens, or does the browsing work without problems.
The easiest way to activate DUN would be to use PDAnet, and connect via bluetooth from a DUN-client device.
I can do this easily from my TMo N1, but I'm curious to know whether this is a way around the tethering problems people are having.