I was thinking a gambas GUI using gb.gui so that it looks nice in GTK and QT.
not sure what all we need in the background... but it should be able to do the same things k3b does
burn cd and dvd images
burn data discs, audio and video
maybe (lots of work alert) process audio and video (convert mp3 -> wav for cd's)
I'm sure we can probabbly use lots of existing libraries for it... just need to make the right calls