Hello,
I don't see why using a 3D plot for a problem with only 2 variables (price, volume)...
unless third variable is time

(but I'm not sure that it's what you are drawing)
Yep it's time.
Here is a graphic of an hours worth of change on the orderbook using rickshaw.
I just think these things look cool.
http://www.imagehosting.cz/thumbs/3dordebsb.pngI'll have a look at the Qt but I'm having fun messing around with python and js at the moment.I hadn't looked at that project before - now exploring.