Along with recently finishing a build with a 1980 Schwinn Traveler, I just put the finishing touches on a commuter build using a nearly identical frame, this time a 1978 Schwinn Le Tour III.
Both are 67cm frames with 63cm top tube, made of straight-gauge high-tensile steel (1020) tubing, with lugged construction. Stamped horizontal dropouts with no derailer hanger, requiring a "claw" to attach rear derailer to the drive-side rear dropout. Both frames are also a similar hue of blue, sort of like Carolina Blue but a bit darker and more saturated. They're designed for 27-inch rims, and won't take anything smaller with the Dia-Compe centerpull brakes that came stock with both bikes.
Also, both bikes have ridiculously high standover height, such that I can stand over with zero clearance while barefoot, or with about one inch clearance when wearing shoes. This makes the bikes a less likely target for stealing, as no one who's shorter than 6'4" can even stand over the top tube.
I've outfitted the commuter for utility, and I'm very pleased. I used 1x7 gearing, and a rear wheel with 7-speed cassette that I built specifically for this bike. A 13-32 cassette is paired with a 40t (steel) chainring (set at 41.5mm chainline) - the crank came on the Schwinn Traveler when I bought it, and has a chainguard built into the spider so I don't need to worry about pant-legs and drive-side shoelaces, or about the chain falling off.
I took the rear 7-speed shifter, and rear derailer with integrated "claw" hanger, from an old mountain bike with horizontal dropouts and no derailer hanger. The mtb is going to become a singlespeed, while its rear-indexed-shifting parts now work well on this commuting bike.
The flat bar is topped off with bar-ends (which I use when riding along at a constant speed without need to shift or brake), a little horn (rated for ages 3-5!), a speedometer, and a blinking light.
The rear wheel is a pretty cool job. I needed a 27" (630mm) rim because the brake pads are already at the bottom of the brake arms, and can't go 4mm further down to handle a 700c (622mm) rim. I also wanted a 7-speed cassette, since I'm a big guy (I weigh only 180# which is light for my height) and nearly always bend the axles on freewheel hubs, unless they're 5-speed.
I used a Shimano Nexave silent clutch freehub (b/c I got it for cheap, and it had good mtb-worthy seals on it; I don't really care if it's silent) and spaced it down from 135mm to 128mm, which requires me to flex the 124mm-spaced dropouts a bit when installing the wheel.
The rim is an NOS Araya single-wall, 36-hole rim, relatively light at 480g. Wasn't the easiest to build up - it's relatively soft - but should be durable enough.
I used DT 14/15/14 double-butted spokes and laced up the wheel half-radial: 3-cross on the drive-side and radial on the non-drive-side. The hub isn't rated for radial spoking, which officially voids Shimano's warranty (like I was ever going to use it on a hub that I bought for $15), but since the non-drive-side spokes are significantly lower tension in a highly-dished road wheel, the flange isn't actually endangered. Plus, non-drive-side spokes don't need to carry much torque in a dished wheel, and the fact that radial spokes don't carry torque will mean less fluctuation in the already-low-tension non-drive-side spokes, so less likelihood of spoke heads breaking from fatigue. Or so argues Sheldon Brown. It mainly just looks really cool, especially with the spoke washers and spoke heads all on the outside of the non-drive-side flange.
Here are a few pictures, which are linked to a gallery with lots of pictures of the bike. The first two pictures are linked to a main gallery with pictures of the bike. The picture of the rear wheel is linked to a specific gallery with pictures of the rear wheel (which is also linked from the main gallery). There are also pictures of my previous commuting build with the frame, with drop-bars and and a 1x5 drivetrain with a 5-speed freewheel, linked from the main gallery page.