Keep watching -- I'm almost positive that Tamara at Rainbow does have the stock to produce hypo trans leatheries. You may want to e-mail her and ask if she intends to breed any such dragons any time soon, and, if so, when. I have found her very friendly and easy to work with. That said she's the only breeder I've ever bought from -- Pele is my first ever "purebred" dragon, as opposed to a random-bred petstore dragon -- so I don't have a lot to compare to. Still, she replies promptly to email, so it's worth asking, I think. I remember when I was looking over her site a month ago, there was a hypo leatherback that was het for trans. It's sold and gone now, but like I said, it may be worth adding her site to your list of ones to check up on.
Good luck in your search!