Although the focus of this post is narrow, I figure it may help someone out.
I have a Dish remote (6.3 IR/UHF PRO) and found that when using the VCR mode button, the Sony DVD code 617 worked the best with XBMC on Raspbian (RaspBMC - version June 2013). The only quirk I found was that the left direction button doesn't work. Its not that major of an annoyance, but perhaps after enjoying my flirc for a few days I'll see if I can resolve the issue.
Thanks to Jason and the rest of the team for developing such a great product.