As the title says, combine the SVP Project with LiveStreamer and you can enjoy your preferred Twitch.TV streams in full 60 fps (interpolated) glory via Media Player Classic.
If you choose to forego MPC, you can instead output to VLC.
LiveStreamer:
http://livestreamer.readthedocs.org/en/latest/#SVP:
http://www.svp-team.com/LiveStreamer supports all platforms, however note that SVP is for Windows only and only runs via MPC.
Quick install for the lazy:
1.) Install SVP
2.) Install LiveStreamer
3.) When prompted after the LiveStreamer install, modify the displayed config with the full path to your preferred media player's executable - for example by adding the line player="D:\Apps\SVP\MPC-HC\mpc-hc.exe" (obviously replacing mine with your own relevant application path). Save the config.
4.) Next open a command prompt and fire the whole mess up by running:
livestreamer <stream URL> <quality>
For example:
livestreamer twitch.tv/capcomfighters high
Your defined media player will then open up, and if you've opted for MPC as bundled with SVP, your stream will render at 60 fps.
I've been using SVP personally for a good while now, though never considered combining it with Livestreamer until today. I used this method to watch WNF tonight and the results were awesome - it makes live streams for SFIV much better, especially considering how it is a native 60 fps game. After doing this, I discovered that a few DOTA players use the exact same method to watch their streams on Twitch also which makes sense. 60 fps makes the action so much clearer.