Since trekking bars are a bad design, basically flat bars without even useable horns, your best bet would be to go to some Rondo bars, etc... If you want them for the brakes, I would still probably mount real levers on the tops, but I haven't though that one though, though I have one bar where it could certainly be done...

If you want to bend ones that aren't heat treated, which should be all of them, they are pretty cheap for the most part... Fill with water during deep winter, or freeze water, then bend the frozen bars the way you want them, then melt out. Don't touch the ones that are heat treated, if you can find them.