0 should be on the right, not the left, since EQ starts with 1. I'm sure down the road you'd want to be able to add labels to those keys.
That looks really useful. Is there anything EQ-specific about this program? I could see it being used for other games as well. Could it be used to switch between any kinds of programs (e.g. Word, Excel, etc)? If so, perhaps it could be just a generic task switcher, which would avoid any potential EQ-specific complaints of cheating. Having a little task switcher for a group of windows seems like it would be useful in many different circumstances. If it's not too much trouble, one suggestion for the buttons would be to make them more generic. Rather than just sending a number, allow people to set what the label should be and what text it should send. I might want to make a button with the label 'Cast DoT' and have it send the text '/cast 1'. Using the hotbar shortcut of the number works as well, but having a label on the button and having it send user-specified text will make it more convenient and flexible.