Most compact solution for external monitor for 2011 MacBook Pro
I purchased a Wavlink 2.0 USB to HDMI/DVI adapter and its working fine as of now with my MBP. Text editing and movie watching have not been an issue. 

My monitor is an old HP 2311x. YMMV on different more high res monitors? I had to install their software for my macosx to get it to work which was not so hard. 

There are some wonderful details about this technology.