Maybe the crappy stripped down 3 speed with the bars flipped updside down version can be called a "nuovo path racer".

But I actually think co-opting another historical term, "scorcher" is a better and more relevant moniker. This also conjures up the romantic image up tearing up hard-pack gravel trails, laughing wildly like Snidely Whiplash, and scaring the petticoats off gentle women out for a Sunday buggy ride.
To the OP: I've found that a stripped down 60's Raleigh Sports outfitted with 700c rims and 28mm tires, in a size larger enough that you can have the stem buried with flipped bars and about a inch or two of post under your B-15 makes a very suitable mount for this kind of work. You have to mess around with filing the drop-outs a bit to use good road hubs and re-spacing the front and rear drops. These frames can benefit greatly from a proper alignment as well. I'll post some pics of mine later.