One of the Cycling+ magazine issues last summer described vintage british parts and the boyhood of the author. As a boy this guy got some cheap 26" sewups at a swap meet, and he hanged each one from a tree with a bucket of cement for 1 week. Then he glued them to his 700c rims and got a year of service from them !!! Then in an audacious move he wrote to the manufacturer complaining that they only lasted a year and got a 75% off coupon for a new pair of tires! And they were 1938 tires and this was in the 1950's !!!
You can probably do the something similar today if you can locate a 27" sewup rim (relatively easy) and a bucket of cement (relatively hard, with all the corporate house-building these days ... *snicker*.)
- Don Gillies
San Diego, CA