Great start, I have to say. I'm not sure why you don't think this Harry belongs in Slytherin, his treatment of the Dursleys would certainly put him there. He doesn't seem to have any other traits in abundance. The bravery to kick Dudley in the nuts, the willingness to work hard to actually streak to get his relatives to back off...I'd say anywhere but Ravenclaw would make sense. Harry doesn't pursue knowledge actively enough to fit in there.
Looking forward to more.