Hi well I have size 15 feet. I've spent the best part of 2 months searching for size 15 boots. I only ever found one site (snowboards4u.co.uk) who had these in stock. I met the guy at a trade show I went to and out of all of them he was the only one with that size in stock.
They ran out of 15s ages ago and there won't be any for sometime. Given that it's either buy 16s or none at all. I went with those.
P.s I was also told to have slightly larger boots than my shoe size.