Forged (thick & strong) Dropouts:
Horizontal Dropout Campagnolo 1010 you want THIS	Horizontal Dropout Short or maybe this	Semi-Vertical Dropout but NOT this	Vertical Dropout and NEVER this
Stamped (thin & weak) Dropouts:			Investment Cast
With Hanger	Without Hanger	Raleigh 3-speed	Track Fork End Not really a 'dropout'

Where do you get this sort of frame...? I might recommend your local Goodwill store or Value Village or Saint Vincent De Paul store or a neighborhood garage sale.

Keep in mind that if you find a frame designed for 27" wheels (as opposed to 700c), it might work GREAT! The extra room means that you will have gobs of clearance for fenders and beefy winter tires. Just make sure that your brake calipers will reach the smaller rims.