artcurmudgeon, I draw a web comic called Square-N-Circle using the tools in Grafpup. You can see it here: http://square-n-circle.weebly.com/
After looking at your comic, and several others at drunkduck.com, I'm not sure mine even qualifies as a web comic, basically because I can't draw as well as the rest of you...y'all are artists!
I found Grafpup because I use OpenOffice Draw, The GIMP and InkScape to draw mine and went searching for a lean operating system that loaded into RAM that had the Open Source tools I use. I didn't think I would actually find it, but, hey, sometimes you get lucky.
In case anyone is reading this and wonders what these programs do, InkScape is like Corel Illustrator and The GIMP is like PhotoShop. OpenOffice Draw is, hrm, not sure...a great, simple 3D tool?