I'm actually using an insanely long stem right now w/ the flat bar.
I use a very short stem with Trekking bars, or drop bars , myself..
as high as the saddle itself..
trekking bars are set up to be a bit higher than the saddle ..
I have a set of 3 piece flat bars for my Bike Friday still a short stem..
like I say pull the stem off , taking bars with it ,
and start over with the right combination,