there is a thread devoted just to 27" tires
see if you can find it
if I get a thread update I'll come back here and post the link
I have bought tires from bike tires direct
http://www.biketiresdirect.com/search/27in-road-tires
I am fond of "armadillos" the smooth ones. I have them on 3 bikes and they come in 27" as well as 700c sizes but I do not see them listed. I am fond of the Marathon tire line, I have their studded winter tire and it's great - so you might really like this one:
http://www.biketiresdirect.com/produ...reenguard-tire

it looks beefy ...