Our plan is to add support for that into v1 firmware, but it also depends on readiness of surrounding infrastructure; mainly if there'll be support for payment protocol in multibit in the time of v1 release (I suppose that the Multibit will be the first wallet compatible with Trezor AND supporting payment protocol).

Yeah, OK. Let's see how much progress Gary makes. Supporting HD wallets is the trickiest part and I don't know how much time I will have - the Android RNG issue and getting bcj 0.10 released have sucked up a lot of my time lately and I need to refocus on other things for a bit. But between the guy who volunteered to do payment protocol, and Gary doing TrezorJ, and Matija already having done the core algorithms, I'm hoping the only parts I'll have to do are integrating the HD code with the core wallet code. Possibly if we're running out of time I can do a real basic HD wallet implementation that only iterates a key once and doesn't generate new keys for each transaction, as that's really the trickiest part (because of the need for lookahead/behind and memory bloat on phones).