Forte Stradas. They're not gumwalls, but they do come in 27x1 1/4, they're cheap and I think they ride and hold up well.
Forté Strada K Road Tire - Bicycle Tires
There's also a cheaper, less puncture resistant version if you're just looking to sell the bike.
Forté Strada Road Tire - Bicycle Tires

There might be something better and cheaper, but I have a Performance Bike just a few miles away, so as far as I'm concerned they're ideal. I'm not really into the whole flipping bikes thing anyway. I've already got more bikes than I need, but every bike I buy or build I intend on using as a rider.