YouTube member Bandticker gives a tour on the recent View Finder to hit the market called the VF Prime. This view finder has a large eyecup and -/+ 4 diopter which most lower end view finders lack. It's been featured on a few different websites, has received some excellent reviews. In this video there's a mention of it fitting a T2i, but with a different sized LCD you may have a 1mm crop on each side. Something people are more than willing to accept for a decent view finder. Should fit Canon 5D Mark II, 7D, and Nikon DSLR's with 3" LCD perfectly. Can be found on eBay here: VF Prime LCD View Finder for 3" Canon Nikon DSLR

Or via Amazon Below


VF Prime DSLR Camera LCD Viewfinder for 3" LCD