I'd go to TC dealers and see about what length and frills level you'd want in your TC (even if you plan to buy used) and see if you can get what you'd like in a short bed. Maybe it'll turn out you need the longbed dually, but maybe you'll like some of the smaller options. They can be pretty nice as well!
We have a shortbed (6.75') truck with a TC that has an 8' floor so there's some overhang. There are bigger overhangs out there and they don't seem to cause problems unless you're doing some really rough roads. It seems that only the real serious backcountry off-roading types have issues with overhangs and when you have trouble with that you should be heading in a totally different direction with your TC.
We didn't want a longbed (or a dually) because we'd have trouble with it as a naked truck around town. We needed a crew cab for kids which makes it pretty darn long already. If no rear passengers, a regular (or even extended) cab with a long bed would be better.
But there are many levels of weight/features among TCs so it's nice to get an idea what you want there so you get the right sized truck.