You could probably order lab-reared or captive cultured American Roaches... They would be just fine to feed. Roaches seem to have little variation in nutritional content, even from vastly diverged groups (Malagasy hissers vs. Blaptica dubia, for example). I'd still feel obligated to rear a couple of a generations out (removed from the parent colony) to be 100% certain there wasn't anything nasty transferred between them, unless I was confident in the source. Definitely wouldn't feed anything wild-caught, as noted.

The nuisance of flight depends on the person. There are plenty of great feeder roach species out there that can fly, and some herps prefer them that way. But not every keeper wants to deal with flyer, and a known pest species to boot! Although with that being said, they apparently aren't as common INDOOR pests as the german roaches, and infestations are only likely to occur in rather unsanitary conditions.

Anyway, I'd just stick to the known goodies as suggested previously. Lobster roaches or turkistan roaches would be a good alternative. Blaberus species, Blaptica dubia, Eublaberus species... Most roaches make for good feeders.