Only 20-some keybinds is really not too bad. I use about 40 or so (all class+cross class abilities, marking icons, special macros, etc), each with their own assigned keys.
I use a Razer Naga with my basic combat abilities assigned to the side buttons and tab targeting assigned to scroll wheel left and right click and target of target assigned to scroll wheel click. All other mouse buttons are default settings.
Then I use a Razer Orbweaver where I use the control stick for movement, the left most column of keys as ESC, ctrl, alt and focus target. The rest of the keys are programmed to be my shift+1,2,3, etc by default and are assigned to things like agro abilities, cd's and the like. Then all I have to do is hold the alt or ctrl keys with my pinky and hit one of the shift+ keys and the modifier (alt/ctrl) overrides shift to make them ctrl/alt+1,2,3 ...
That puts around 50 ability keybinds at my fingertips not even including movement, jumping, targeting and other stuff that I have bound to things as well like the scrollwheel.
If you don't want to get special peripherals then some of the ideas presented by others are a good way to go, such as rebinding some of the farther number keys such as anything past 6 to letter keys that see little to no use right near WASD so they are close by. That and using the modifiers like shift/ctrl/alt+ other keys is an absolute must and is standard for most PC MMO controls.
