You could "re-invent the wheel" which is fun but often gets in the way of the real project. Or you could purchase this UAS and/or consult Skip Miller Models in Colorado. He has worked w/ several universities. The Tempest has more than enough room for all your FPV/telemetry and anything else you want to stuff in it. Designed just for the type of project that you describe.
http://www.youtube.com/watch?v=N8Lb9...RiJ5vA&lf=plcp
http://www.skipmillermodels.com/
http://uasusa.com/ "recently achieved a very successful mission with flights exceeding upward of 10.8 miles above the surface of the earth..... and returned safely to the launch site 38 miles upwind." 57,000 Feet!!!!
I am sure with UASUSA's background working w/ universities would give a leg up in the approval process w/LSU.
Brooks