Is there a mobile wallet that works with a Trezor? Is there a mobile wallet that support using a Trezor hardware wallet to spend coins? Is there an online resource that tracks features like this for thin-clients?
Is there a mobile wallet that support using a Trezor hardware wallet to spend coins? 


You first need an OTG cable and a phone that supports acting as a USB host.

Trezor has not released a mobile version of their wallet.  However they have a Wallet Manager that can be used on your mobile (for Android). This allows you to manage the Trezor (but not spend money). 

For wallet functionality they recommend using Mycelium (Android) with your Trezor which has support for this. Mycellium has an iOS client but it doesn't support Trezor.


  Is there an online resource that tracks features like this for thin-clients?


The only resource that I'm aware of is the Trezor documentation.

Trezor currently doesn't work with Apple iOS devices; it doesn't have MFi certification.