It would be great to have support for Confidental Assets (CA), which is used in the Elements blockchain platform and in Liquid, the commercial sidechain based on Elements. I'm happy to help move this forward, and am available by email at apoelstra at blockstream.com for any clarification or guidance.

CA is described in this blog post: https://blockstream.com/2017/04/03/blockstream-releases-elements-confidential-assets.html
It is essentially the same as Confidential Transactions, which involves the use of Pedersen commitments in place of amounts, alongside rangeproofs, which I believe is already supported as part of Trezor's Monero support. CA mades one of the two EC generators variable and adds a new "asset surjection proof" which is described here: https://github.com/ElementsProject/secp256k1-zkp/blob/secp256k1-zkp/src/modules/surjection/surjection.md

We've implemented CA in full as part of libsecp256k1-zkp, our fork of the Bitcoin Core libsecp256k1 library.

For referenc, the API for making surjection proofs is here: https://github.com/ElementsProject/secp256k1-zkp/blob/secp256k1-zkp/include/secp256k1_surjectionproof.h
and the core crypto functionality is here:
https://github.com/ElementsProject/secp256k1-zkp/blob/secp256k1-zkp/src/modules/surjection/main_impl.h
https://github.com/ElementsProject/secp256k1-zkp/blob/secp256k1-zkp/src/modules/surjection/surjection_impl.h

Cheers