I was looking at some stuff to make a bike headlamp, and I found these LED drivers that can be purchased as voltage regulators OR current regulators. They have one that has a max of 350mA and you can order it with Internal or external trim to get it from 40% -110% of it's rating. So you should be able to get it from ~160- ~385 mA. IT sounds basically like a professionally built DDL driver.
Here is the datasheet for one I was thinking of:
http://www.leddynamics.com/LuxDrive/datasheets/3021-BuckPuck.pdf
Here is the datasheet for one I was thinking of:
http://www.leddynamics.com/LuxDrive/datasheets/3021-BuckPuck.pdf
