Development has resumed on the native OSX driver for Winforms.  This effort is in the early stages, however if you wish to try it out, you can either:

#1: macpack your executable with "winforms" mode.
#2: export MONO_MWF_USE_QUARTZ_BACKEND=1 and GDIPLUS_NOX=1 and run your application from the terminal.

This driver is an unsupported preview for developers, contributions are welcome.