Several years ago I installed de-icing cables on the rooves at a small strip mall. The circuits were all 30 amp, 120 volt. I was able to purchase s/p GFCI breakers from Siemens (at about $150.00 @ BTW) that tripped at 30 ma instead of the std 5ma. After the job got inspected the inspector told me that GFCI protection was not required for this application. None of the outdoor receptacles are readily accessable. I felt better having the circuits GFCI protected though seeing as how the gutters and leaders were all metal.
I know this probably doesn't help you but I would find out if GFP is required or not before making an investment.