I am still having some teething troubles with my build; suffering from frequent resets (sometimes it gets stuck in a cycle of rebooting until it corrupts the SD card) and also has a very unstable wifi. Time for a rethink.
I am currently stripping out the powered USB hub and the Model B, and replacing them with a model B+.
The B+'s better onboard regulator and extra USB ports will allow for me to plug my wifi dongle, a flash drive, the touchscreen and a USB extension to the USB port on the case. This in turn simplifies my powering amd removes the suspect hub from the mix; powerboost straight into the Pi.
The code over on my github is getting very close too - just needs the syntax tidying up and a few tweaks once I finally get it on the Pi!