Another 6’7″ here – but with much longer legs than ‘giant’ above.
I have several 29ers, a 23″ Spesh Rockhopper, a 22″ Salsa Big Mama, a 20″L Kona Honzo (which is fine in the top tube but borderline in the seat tube for me) and a Salsa Fargo XXl (24″) which all fit me relatively well.
I seem to recall that i had an email from Spesh a while back saying they have a demo bike in every size which they can get to the local Concept Store for a try before you buy. Failing that, he’ll struggle to get a test in most shops as they don’t carry such big bikes in stock (Evans may be an exception here given their size). Depending on where he’s located, he’ll have more luck asking for people on here to let him throw a leg over their bikes.
Also, although there are some who say that 26ers are ok for people of our height, i found the 29er route a far better fit for my frame than any old 26″ bike i’d owned.