I would not recommend the A55 mentioned by many others because you cannot adjust the EVF for low light (that was corrected in the A57). I also prefer the A57 to the A58 (except for the low light noise; there, the A58 comes out on top - even better than the A77, in fact - but you are using lightboxes, so this should not be an issue). In case of the A65, the EVF goes from LCD to OLED, which means that there is no lag time (by the way, the A58 is also OLED EVF). The big diffence would be when shooting action sports or other fast moving subjects, but otherwise, the LCD works just fine.
Now, I agree with the comment, if you are planning on going pro, you shoul dconsider full frame cameras... You could probably pick up a used A900 cheaper than the A99, but I would save up and move to that camera. I tried it when it came out, and low light images are AMAZING! Of course, if you do not plan to shoot in low light situations, the crop sensor will do just fine, but as a pro, you need all the advantages you can get, and a full frame is hard to beat when shooting a wedding when no lights are allowed...