Do you already HAVE an old steel touring bike that fits you? If not, I wonder just how easy they are to find. Besides 27 vs 700c, there is also the problem of hub width (which can be dealt with but it is there). I'm not sure if a canti can handle the difference between wheels sizes although I have seen caliper brakes work for both. Of course, this will lower your bottom bracket further as well.

I think you were on the right track with Surly. I've had both the Long Haul Trucker and the Crosscheck. If the main use of the bike is to be touring, go with the Trucker. The Crosscheck is way more versatile but not quite as rock steady as the Trucker. They both make great touring bikes though. I ended up replacing the Trucker with a Crosscheck because I wanted one bike to do everything. Right now it is in cyclocross mode but all I have to do is put the T-Serv tires and racks on and it is ready for touring. I also have a set of road wheels with 23c tires if I feel like doing the roadie thing. And if I ever get tired of gears it is single-speed ready as well (but I already have a Steamroller so that is unlikely).