There's always the risk of feeling buyer's remorse with technology but, realistically, your film won't be any better or worse off no matter the decision you make. 4K isn't something most folks should be concerned about. It's no guarantee of a better looking film if it was projected in a theater and if it's not being projected in a theater it's pretty much a waste of money and resources and effort that could be used elsewhere.
Most theatrical films are still finished 2K (regardless of origination) unless a director has the juice to force production to pony up for a 4K finish. You would think that for $100+ million dollar blockbusters this would just be a given, since they're already spending a mint but that isn't the case. It's still quite rare. Not as rare as even a year ago but it's not standard practice to finish 4K.
Making your own feature, either putting up your own money or getting some from investors, you should save yourself the headache. Spend the money that might be needed for extra storage or an upgrade to your editorial on something like catering, being able to bump your key talent's per diem a bit or the wrap party (or wrap gifts...I didn't understand the importance of these my first indie).
And make sure you even really need to upgrade your camera, considering it's an asset you already own. $1500 goes a long way on an independent feature. I admit I never thought much about the T2i but that was before seeing Kendy's stuff...
...I'm a GH2 guy and know it's technically a better camera but operator talent (along with the quality of the content) can render technical jibber jabber and megabits rather meaningless.