I think for the big boys out there, there are a couple of great new choices about to hit the market. The aforementioned Ronin joins a small group of boats that really do accommodate BIG guys. I think Fluids designs are there too - very roomy even in the smaller sizes.
I was fortunate to get to paddle all three sizes of the Agent, thanks to some lowly friends in lower places, as it went through development. The one thing I found to be consistent throughout was how spacious the thing was. I could paddle the smallest one for long periods of time withot ANY discomfort, though the 6.2 would be the right size for me (I'm 5'10 - 16
. The 6.4 seems to be carrying that same theme in it's design and I think it's going to work out well for you big fellas.
Bottom line, get your ass in the boats and try them first.