3IV Treecko? I'm doing a Meowth training session (a 5IV and a 4IV, going to try to generate some perfection there), but I can try this if I get a Treecko in my game, or at the very least in my Black game where I do have a Treecko and a perfect Ditto already. 3IVs is tougher there, however, as the Destiny Knot effect only applies in 6th gen. for five random IVs. Breeding and importing one could be done, however, to try, or if you want to supply a Treecko (if you want a specific nature, that one, though I can take any), I can breed the heck out of it. :)
Note that I can also inbreed. When I get a 3IV (4IV is also easily possible, but rarer) from the first parent, I pull it out and level up the selected new parent before putting it in the daycare. By then the Destiny Knot picks a minimum of two 31 IVs (three from a 4IV and my Ditto), so getting the fifth should happen with time unless it keeps picking 31 in the same stats on a regular basis. The 6th would be harder to come by, however, and is completely by luck. But I can give it a shot for you. :)