hi jayb, no one to my knowledge make a folding tip brake lever for the tenere, a few on here including me have made up ones by welding on folding ends from the likes of xr's etc.
the easiest and simple solution is cutting the lever 'pad' to a more sensible size, i've yet to find fault with proper off-road pedals such as on a ktm, tiny and fixed!. the one i really don't get is the t*tech, you pay out for a massive clumsy albeit pretty extension which is as much use as a chocolate tea pot!
don't forget a brake snake is perhaps the biggest help!
a funky artistic shot from this time last year