Larry at gunwukz is a great guy and the prices and selection of his sigs is really good as well. I did a transfer with him a couple months ago. One note, he runs this business from his house and you need to call him before showing up.
Speaking of multiple transfers, I believe Hill Country Black Rifle will transfer as many guns as you can fit on the 4473 for what they charge for one ($25). I would have to double check with a phone call, but I do remember being told that last time I was there.