Well this is an proof of concept so to speak. Not really a thing ;-). What i do here is generate scad files. I was playing with that thought for a while now. Because its a bit strange. I use one programming language (action-script 3.0 and flex in my case) to generate the other.

In this case for the polygon method within openscad witch is powerfull but hard to read. So a made the visual helper for generation polygon call with a bit of extrusion

Weird but it works what do you think mad or mad science ;)

The small air app does not have any undo functionality and you can only draw on a grid, it was just to test something maybe i will add stuff to it ? should i ?

http://www.youtube.com/watch?v=0oSW9zlKsZ8

Update 14 Jun 2011:
Thanks for the great response but a bit of warning is in place the fxp source code is, well.. how do is say it.... very sloppy ;-) , just so you know build it 2 or 3 hours or so ( hack hack )

Update 13 Aug 2011:
Still working on it but not ready for its first release :-(
Some hints

• Layers (one layer is one openscad module) each layer its own color
• Adding and Deleting of Points and of course Moving points Splitting of segments
• Curves (Maybe)
• Save files (some json or xml) so you can save your work
• Web based and AIR app
• Etc Etc ;-)

Update 2 Aug 2012 :
New version at
http://www.thingiverse.com/thing:13348
Or
http://www.protorabbit.nl/?p=32

• Install the air program (you need the air runtime from adobe)
• Look at vid on youtube
  http://www.youtube.com/watch?v=0oSW9zlKsZ8
• Run the app draw some polygons
• Save it
• Open it in openscad
• Check Automatic Reload reload and Compile in open scad
• Make some more polygon and save
• See openscad update (cool)

the scad files are some examples of what it generated
the stl are the results from the scad files
the fxp (is a zip) and can be imported into flash builder