Yep, they will do full canvas for an additional $50. I believe they also needed an additional week or so since it requires special attention. In my case, they actually mixed up the order and made my suit half-canvassed before realizing their mistake, which resulted in additional delays.
Actually, when I first placed my order, Andrew's brother Calvin seemed to think that there was little benefit in requesting full over half canvas. He said that fusing has improved to the point where it isn't really considered a negative. It still seems worthwhile for such a small markup, though. Will have a better idea when I see the results!