I'm fortunate to live in an area with endless gravel roads. Currently, I have a 56 cm Nashbar Steel Cyclocross bike. The bike is great for riding gravel, other than I get heel strike when I put panniers on the bike. This is annoying, since when I go out exploring gravel (usually in the fall/winter/spring), I like putting panniers on the bike to carry maps, lunch, first aid/survival gear, and spare clothing.
So I would like to use most of the components off the Nashbar bike and upgrade it to something more suited for riding with panniers, without heel strike, and light touring. My miles will probably be 70% graded gravel (short, steep hills), 25% pavement, and 5% rough doubletrack, I would like to eventually do light touring, of the 2-4 day variety, with no more than 30 lbs of gear (I'm a backpacker so I already have lightweight gear). 90% of my miles will be day expeditions (<10 lbs of gear), the other 10% will be light touring (~30 lbs of gear)
My other musts for the bike are cantilever brakes, reasonable cost (frameset of <$700), and of course plenty of braze-ons.
I've narrowed it down to two frames:
Black Mountain Monstercross [56 cm]
All City Space Horse [55 cm]
Which one would be better for my style of riding? The All City looks to be more of a traditional touring bike, with longer chainstays and a lower bottom bracket, while the Black Mountain looks a little more racy. I'd just get the Black Mountain, except I worry that the chainstays aren't that much longer than my current bike (432 mm vs. 425 mm) and I might have heel strike anyway. The All City has longer chainstays, at 440 cm, but a lower BB, which I could see being a problem on doubletrack.
Here are links to the specs of each bike:
Current Bike: http://www.nashbar.com/bikes/Product_10053_10052_553817_-1___202339
Black Mountain: http://www.blackmtncycles.com/p/black-mountain-cycles-frames.html
All City: http://allcitycycles.com/bikes/space_horse