When shooting video don't move your camera much or do a lot of panning.

I would skip the T4i and grab a used or refurbed T3i. Remember that a DSLR is a system, and you will need to budget for lenses, support, lighting, media, power, etc.

yep, i think you should get a t3i or a t4i. for filming i think you should buy old M42 lenses. i got a Helios 44M for like 20-25$ with an adapter for my GH1. at F2.8 at the center it's much sharper than my Panasonic 14-42 kit lens at F3.5, and at F5.6 it's MUCH sharper everywhere. the focus ring spins much more, that's good for filming, and my Pana 14-42 lens is focus by wire, so it's pretty much useless for filming.