Hey Kangal! I read all you detailed features and I found sometime to play with 3d max
I really liked your game pad and detachable add-ons idea, but I thought I'd crank it up a notch... or two...
I hope you don't mind
So... I call the monster we created 2ch'd (touched) as it "is" a full touch device from top to bottom and side to side. Push to slide fully customizable pad (keyboard/joypad/media controls). Push to open connectivity interface. Alternative touch controls on both sides (eg. music player)
I was going to update that concept, I had some tweeks to add to it but I recently flew away for a week, but am back now. But I've had a lot of work gathered for me during that week, so I was unable to finish and submit.
Hopefully I'll get enough time to do it this week (I pretty much finished those extra work) and you can take a glance at it.
Oh, and it looks real nice, I wish I could make a 3D render