Originally Posted by
Metaluna
There are at least a couple of frames around that are designed as jacks-of-all-trades that can work well as either a geared or SS bike, mainly due to having horizontal dropouts in addition to a full complement of brake and shifter mounts and housing stops. I'm thinking specifically of the Surly Cross-Check and the Salsa Casseroll, though I'm sure there are others.
However, just as unneeded/unused braze-ons are a minus on an SS rig, horizontal dropouts are a bit of a PITA on a geared bike, so the "master of none" part of the aformentioned old saw is appropriate, IMHO.
Horizontal dropouts are fine for a geared bike. (been used on road bikes forever up until almost recently). If you have a rear deraileur, all you have to do is pull the rear wheel all the way back till it sits at the "bottom" of the dropout, and tighten the axle bolts or skewer. No worries.