I informed SK in September 2013, Trezor does support alt-coins, only problem is:
Trezor device has already support for various altcoins. The problem is
surrounding infrastructure; even Litecoin team was unable to give us proper
support tools to integrate Litecoin into myTrezor. However altcoin support is
one of things we'll work right after we start Trezor eshop and things settle
down a bit.