Good start Kurt.
My only arguement here with cube sculpting in Zbrush is that you wont get decent edge loops out of it without resorting to retopologising which is a complete waste of time to me at the offset, its fine if all you are going to do is sculpt. You see alot of this on the Zbrush forums, where dude just sculpt,which is fine but if you want to animate it you cant unless you resort to the aformentioned retopologising
If I were to do a sculpt from scratch in Zbrush I would use the zspheres as they are excellent for Loops as soon as you start placing them and are completely editable all the way thru so you can jump from spheres to poly without much hassle.
Just my 10 pence worth of opinion
good job though