A77 pixels are NOT tiny, crammed, etc
G3 would be more suitable as it has more pixels than GF3 or E-P3. I guess they are very close to A77 pixel density (or GH2).
Though I hope you realize what high ISO performace those cameras have.. (or to put it differently, lack of usable high ISO :D).
Btw. depending on AA strenght, A77 will need a really good lens. If they add bit more mpix they wont be able to feed it. SD1 is quite similar example, great resolving power, but no lens to match it.
Explain Pentax 645D if that is the case