Hey Adam -- hmmm -- from what I've seen, 445/450 is about as long as you're going to find in a production bike (700c or 26" based)?? Not an issue for me, but then I'm not tall/only a 41 (Euro) shoe size. I'm not sure (others may know) but I think the Tubus can be mounted 'around' discs (using adaptive hardware). Otherwise, you might be stuck with custom? I know e.g. that Thorn does their custom frames with xlong chainstays (so would others), but the cost ...!!