daatse:
is it simple to program a ATtuniy using the arduino or does that require me to reinstal avr studio and the whole shabang?
No need for the whole package. I haven't built a Tiny setup (no Tiny-sized projects just yet), but from what I've read around here, if you use one with good support you should be all set. Hardware wise (Arduino as ISP) you're fine.
My interest is piqued by the matrix setup. Might be worth trying that out first...