Had the same problem with my MacBook Pro 13". It started with my trackpad failing, but after restarting the computer it would work again, or after leaving it cool down. Still, as time passed by, it stopped working at all and the keyboard started to fail as well, so I was left without trackpad nor keyboard to use my Mac. Sadly, the problem started after the warranty expired and I was living in Colombia (a country with limited Apple support). I decided to wait until I came back to US and scheduled an appointment. They charged me about 96usd, 79usd for the technical support and 10.23usd for the hardware cable ("SVC,CABLE,IPD FLEX,HA COPPER,13" MBP" - Part Number: 923-01376), plus tax. It started working perfect immediately and the tech guy just took like 15 minutes to do the repair. That even fixed a problem my computer had of not sleeping, probably because of the malfunction of the keyboard and the external mouse, can't really tell why. But still, the fix is recent so I'll wait a few months to know if the issue is really fixed. I didn't want to mess with the hardware myself, specially not knowing what the problem was neither the exact part to replace... but if someone can't get to an Apple store and have this same problem, they should just look carefully for the part on eBay or somewhere else, buy the tools (special screwdrivers for Macs) and change that cable themselves.