So I've investigated this heavily, and jailbreaking an iPad isn't, and shouldn't be the answer for many reasons. The way Citrix does it is there is a companion app that is run on the iPhone that presents the trackpad commands to the Citrix app on the iPad, and VMware could do this but it's kind of a cheesy work-around. I would like to use both my full-sized BT keyboard and regular mouse when using my iPad for VDI, and my message to Apple is thusely (and if someone knows how to get this to Apple outside of the suggestions forum I'm all ears!):
"Dear Apple, your iPad device is really nice and wonderful, and in my experience I have found a use for your iPad above and beyond what you have anticipated, and this use could represent a market that was not anticipated by Apple and could increase the revenue of your company as a result. What is this use you ask? Well it's VDI, or Virtual Desktop Infrastructure, and it's where I'm using your iPad device as a Thin Client to access my corporate desktop. Using VMware's View, this works very well, but one added item on your part would enable the replacement of my PC and laptop by an iPad, and that would be an API for third-party developers to access a bluetooth mouse from within the application. With that, I could connect an iPad to my monitor, and use my bluetooth mouse and keyboard in the VMware application and duplicate the Pc or laptop experience completly. Why would this benifit Apple? I'm glad you asked. What this would do is shift the conversation IT departments have around should I by a dedicated device for my VDI and maybe an iPad as a secondary device for select users to I will just buy an iPad for all my needs across the board.
I believe this is a simple API addition that would not represent any major risk to the core iOS security and open up a new enterprise market for Apple in the space of the iPad devices."