Im guessing the mainstream new user wanting to write a program would go the python route, which would not require scratchbox dev environment at all.

You could code on device or setup python on desktop and do development there. The most comparable method is probably to use glade 2.10.0 to design screens (which you would do on linux desktop or linux vm appliance)

This page shows glade which would be mostly the same for python :
http://nat.org/demos/gtksharp.html

Mono also exists and i'm awaiting the next release of this but the version thats already out works somewhat and works with glade. The mono route is not mainstream for NIT devices though... possibly once its refined more.