I'm sorry, but it just doesn't get any more ergonomic than the Intellimouse Optical
For mainstream mice, this has also been my experience. I personally would prefer its height be a little lower with the side buttons, but I currently haven't found a mouse more comfortable than this. The MS Comfort mouse 6000 is also very good for a palm grip, but has a delay in the scroll wheel button and aggressive angle snapping. I just wish its 400dpi sensor in the IMO was enough for me.
Perfect mouse for what you want, and it doesn't break the bank while being customizable: Mionix Naos 3200.
The problem with the Naos and Func MS-3 is that they're both exclusively for people who use a two finger position instead of a three finger one. I prefer 3 finger grip (ring finger on the right mouse button, middle finger on the wheel) as it gives all my fingers access to more buttons, whereas mice like these assume you're holding the mouse only one way.
I've considered buying this mouse before, but I read that the scroll wheel is shoddy and will break after a while:
That looks like a great shape for a mouse for palm grippers, (they make both right and left hand models). Why is this the ONLY COMPANY making mice shaped like this? Why aren't there a dozen knockoffs of this shape? It strikes me as intuitive that a mouse shaped like your hand would be comfortable, but apparently most companies don't want to do that.
Again, this isn't for claw grippers, but you guys already have lots of good options.Edited by chilledinsanity - 6/11/13 at 1:16am