The bike looks fantastic by the way, and I those Marin FS are a blast to ride.
I had a Mount Vision myself but had to sell it because at 6'2" it was just a tad small for me at 19". Since then I've been on the look out in case a larger Marin FS comes up, but as the largest I'd ever seen was 19" I began to fear they were never made in a larger size.
Out of curiousity, what are the head tube and seat tube lengths on your frame? The head tube at least looks a fair bit taller than my old 19" frame.