Write to adsense; once they get a number of similar suggestions, they'll think about it - and we must be about due for some new shapes!

I think the greatest need is for something between a banner and a leaderboard. Say, 600x80 containing 3 ads, or similar.

Why not a 800*600 MFA special? :p

A Circle? An Oval?

What we need is for all the ad units to have the "ADS BY GOOGLE" text to be moveable to either the top or bottom of the ad unit left or right.

Ads that have the text at the bottom - which are the Leaderboards perform better than the rest because people click on the ads and then realize that they are ads....

Thus, people using the Leaderboards on their pages will find much higher CTR.

Can anyone confirm this?

Just build it out of smaller adblocks and but them together with no space. I have had them actually fuse together in certian placements, borders and all.

How about a 468*120? (Double a standard banner)

Some places have this size already available (Amazon, Chitika) and call it a "blog banner." (I suggesed this size to YPN also)

I will write to them then... I think we seriously need new sizes.
I'd stack 3 smaller ads on top of each other, but then I'd be using up all my available ad units...!

New shapes sound good too... oval and circle? How about heart shaped?