Have a look at some my threads about fitting bullbars. I probably should call my bar option something other than a bullbar. I use upsidedown cut back drops. With the road race brake/gears mounted vertically like old fashioned low profile time trial bars. Not aero bars.
Bullbars with horizontal mounted levers fold better but I dont like them and with the upside down drops you get an extra hand position.
Yes it looks like shortening the stem would help with this mod. There are a couple of options for QR stem extenders. Dahon for instance but the usual solution is a Alba Halo with a QR added. It should be perfectly safe enough with the later. The dahon is QR but marginal to hold the bars and overly long for this application at about 6 inches.
Mezzo modders have added a single QR to a 2 bolt stem(locktite other bolt) and not had issues
afaik.
There are pently of alternative QR stem solutions.