I think calling the little protrusion on an AE-1 a grip is a bit fo a stretch. That said, I still find my AE-1 to be one of the nicest cameras to hold - so while it may be small, it is very effective (that's what she said?).
Overall, I seem to prefer small grips. AE-1, Nikon FA, and OM40 are all excellent examples of what I find most comfortable. I have two OM10 bodies and an OM2SP, I find them noticibly less comfortable than the OM40. Even my wife (who has no interest in cameras) commented on the lack of finger grip the first time she picked up the OM10.
I'm thinking of getting a finger grip made for it. The Panasonic GM1 has an interesting little milled finger grip add on that I think could be copied nicely for the OM10 bodies. I may bug a friend with a lathe to see if he can make one, or I may just CAD one up and see if I can get it 3D printed.