I like gimp very much and it is a very helpful portable alternative if your used PS, but when it comes to svg or similar, gimp loses extreme efficiency. And for desktop use Illustrator does most of what I need, but I also work on other people's computer, where most of the time don't have Illustrator, so what about making Inkspace portable?
Inkscape would be cool.
But if it is Inkscape you want, please use the search first, and you'll find lots about it. You will find a couple portable versions, but an official version is coming soon.