Hello,
Disclaimer: *This is no advertisement.* If it doesn't get clear from the following, I'm in no way associated with the owners of StackOverflow.com. (I mention this, because after reading the mail again, it could be interpreted the wrong way.)
The Q&A platform StackOverflow offers open source projects free ad space to recruit new developers [1]. The method is quite simple: If you want to have an ad there, place it as answer to the question linked as [1] and hope for other people to upvote it. After a certain threshold of upvotes it gets published for free on stackoverflow.com.
Since Inkscape hasn't got an ad proposal there, yet, I thought I'd suggest one. It must be 220px x 220px and GIF or PNG, and my suggestion is [2].
If noone on the list objects (especially against using the Inkscape logo) I'd upload the proposal to meta.stackoverflow.com during the weekend. If there are suggestions for other banners, mine can easily be exchanged afterwards. I write this mail just because I don't want to do the ad kind of behind the back of the Inkscape developers.
By the way: What would be your suggestion for the backlink the ad should point to? The wiki? The Inkscape homepage?
Cheers, Manuel
[1] http://meta.stackoverflow.com/questions/31913 [2] http://static.manuel-strehl.de/StillImage/inkscape_promo.png