Regarding altcoin integration, I believe satoshilabs are happy to add support in the device,but they won't create wallet for them. They said that many times. What it means is that if Electrum works with Trezor, Electrum-LTC will work as well. If there is ever in the future altcoin X that they decline to support, I'll type the one line here: https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki#Registered_coin_types and here: https://github.com/trezor/trezor-mcu/blob/ed2e0d081b1f92fd4cf165e7bd426ef0b49e9675/firmware/coins.c myself.