I have trackpad app... it doesn't really work (doesn't disable track-pad)... I'm using the official MicroSoft wedge mouse with my Surface, and the trackpad (which used to make my life miserable on a continuous basis) is only messing with my life on a periodic basis (a few times a day).
I googled for more info and got instructions to do the following:
Go to "Devices and Printers"
Select the keyboard cover device
Select the trackpad driver settings
Click "Change settings"
Disable the trackpad driver.
Yay! It works! No more trackpad.
Until I remove/re-attach the keyboard (or do some other thing that I have yet to figure out) and magically the stupid trackpad is working again and messing with my work. I should also mention that occasionally the Surface loses contact with the wedge mouse, and the only solution I have found is to power down/up and the mouse starts working again.
Now get this...
I repeat the trackpad driver steps above, and finally get to the trackpad driver settings and it says that the device is disabled.
If I ENABLE the trackpad driver, the trackpad will stop working again.
I suspect that this is because I have disabled the mouse with the the trackpad app (when the trackpad driver is disabled, it is not possible to change these settings in the app at all, even though the trackpad is working with all the app switches set to OFF).
IMO, this is a bug in the Surface and the trackpad app settings are only checked when the driver settings are changed.
This is annoying, as it takes quite a while to get to the driver settings because "Printers and Devices" has to sniff out every network printer in the world before it finally lets me get to the trackpad settings.
I'll check back here once in a while to see if anybody has an official solution. I expect this problem will go away in a few OS revs because it is a real problem.