The 11-36 cassettes are supposedly going to drop when the big manufacturers begin the whole new 2x10 mountain groups. The idea will be to ditch the fussy triple in favor of a 36/24 double or things like the truvativ hammerschmidt. While i do see how a triple with indexed shifting is a PITA, i don't know if this 10speed ultra-wide range cassette is necessary. Articles i've read have suggested that the current long-cage atb derailers (SGS, etc) will accept the 36t cog, but this remains to be seen. Whatever; the new XTR/x0 groups will absolutely feature new rear derailers that can handle the 36er.
For the cyclotourist, this basically means you'll be able to have a 3x10 mtb-derived drivetrain with a super-low 22x36t granny option. As someone mentioned earlier, i don't know if you'll notice much difference between that and the current 22x34t grannies that many of us are rockin'.
Personally, i feel like a 22x34 gear ratio is low enough for anything that you're likely to encounter. Steeper and crazier hills than that, and you might be better off pushing the bike up the hill. I know many ppl do long for a lower gear, but really... 22x34 is pretty low..
hth,
-rob