Heh. Indeed, you could make the whole thing a LOT smaller, more reliable, longer-lived (battery-wise particularly) and single-purpose without the Arduino architecture as well. But time-to-delivery can be pretty darned quick with the lego-like, stackable world of Arduino/Pi/whatever. And I'm
not a qualified engineer so wouldn't have to work through all of the wincing/cringing/eyerolling that a 'qualified engineer' would while working with these toys. ;)
http://arduino.cc/en/Tutorial/YunDatalogger
And you can get pretty crazy with the module stacking. Maybe video and cellular, and wear it on your head for live GPS and video (and barometric pressure, of course) streaming! :) Of course they would cost $300 each, weigh 12 oz., and need to be mounted atop a construction helmet. AWESOME for your larger model rocket, but ...