I think calling e85 a boutique fuel is a bit short sighted Ash, I can now access this stuff 3 minutes from home and the list of outlets is growing.
6 weeks ago it was available in a couple of servos in the southern states, have a look at it now.
Unless you are driving your line in some pretty remote territory I reckon it will be as available as 98 ron within a year or so. Its not always easy to find either.