You can use one seed for all cryptocurrencies. Right now we support BTC, NMC and LTC; With proper support in *coin software you can change currency in runtime and you'll see *coin history and balances. We're working with Litecoin developers to support Trezor in their client.

really looking forward to ordering one and using it

I just got my trezor dev unit. Will look into Litecoin support.

I love the matrix used for entering your pin. That way even if the computer you used is compromised, they can't steal your pin because you will be typing in a different one each time. The only problem is that the matrix only has 9 spots. Nothing maps to a 0. My original pin had a 0 in it and I was stuck. I had to modify the emulator on the RPI to hack in my pin to change the pin. I suggest you do a server-side check on a new pin to make sure there's no 0 in it so that one doesn't accidentally make this mistake.

One more suggestion, allow reverse mapping of pin matrix as that is what's easiest for someone like me to remember.
For example, let's say your pin is 1234 and you are shown this matrix:


Right now, you'd have to find the spots that have 1,2,3, and 4 and then figure out the index of those spots. In this case it's 9872.
My suggestions is to also (or only?) accept the reverse mapping... where you lookup the spots that represents the index 1,2,3 and 4 and type the numbers in those spots, so 9485 (the first 4 numbers in the matrix)
The main reason is that a lot of people use visual memory and they will remember the location of their pin and it's much easier to figure out the encoded pin this way.

P.S. Is there a better place (forum/irc/etc) for suggestions like these?

I'm already aware of this problem and I'll fix it. This may happen during LoadDevice call, where PIN is entered directly, not via PinMatrix.

Of course we are not sending the matrix to the client. If we did, it would defeat the whole purpose of it. I meant "indices" instead of "numbers" in this sentence:

Yes. It's quite straightforward concept, but hard to explain without any visualization.

TRUE

We already had some discussion about this with slush and we certainly want to come up with an "Identity" BIP (that builds on top of BIP32). That way it will be standardized and easy to implement.

I assume it would be possible to use Trezor for signing of arbitrary messages (provided some software effort)?

It would be cool to have a python library so one could easily play with it. If you go for Electrum please try to make it a separate and generic module.