I'm not sure if Pi or any of the ARM based boards will have the required grunt to do this, nor will the software run (suppose it depends on what software you use)
I was looking into doing something like this as well. A tiny little box mounted onto the mount and then access it remotely.
The best i was able to come up with was a Fit-PC2, with a 1.6ghz atom and 2gb ram it should do everything (all be it a bit slow).
Sadly they are very exxy to buy in Australia. If you want to import one then they are cheaper.
http://www.yawarra.com.au/catalogue....pc2&s=fpc2-bus
http://www.yawarra.com.au/product.ph...ctCode=HW-FPC2
Given that it has 4x USB ports, it's almost a USB hub in itself.
Also if you want to go down a mini/nano itx route:
http://www.mini-box.com.au/