If you can get a 25.4/mtb flat bar, then the Sunlite short stem might work.
http://www.amazon.com/Sunlite-ATB-Ur...ef=pd_sbs_sg_3
Niagara Cycle also carries a XLC 4 bolt front pop clamp that's more for BMX, but it's a quill stem and in the "Road" quill stems section:
http://www.niagaracycle.com/product_...ucts_id=447545
Both are just 21.1mm extension. Short enough for ya?