In that case, every bike manufacturer's track frames has different geometry and some are virtually indistinguishable from a road frame, others have totally different geometry within the track frame category. The vintage Fuji road bike I have has a straight top tube, even the atb bike I have is a flatter top tube than what today's designs have incorporated for mtb/atb frames. Both are/remain mutli-gear. And going with different front forks with various rakes and angles is going to change the bike's stance and road manners too.

As for throwing a chain tensioner on one (SS/FG that is), that defeats the concept of a direct drive bike, crank gear wheel to rear gear ? The first tensioner increases chain length, adds weight to the bike, creates an inefficiency in the drive train.