I'm after some examples of bright, colourful, whimiscal, but single tier designs. I suspect I'm trying to cram too much onto one poor round cake.

Thanks!

By whimsical, do you mean tapered on the sides, or just the designs on it?

I work in only buttercream, but I consider this to be a whimsical design (in the style of Peter Max) on a 12" round:
http://www.sugarfrosted.com/displayimage.php?pos=-2667

If I have misunderstood your request, I hope others chime in to offer more suggestions

Sugarshack has a cake that was for a baby shower, but the colors and decos are so wonderful you should take a look. One layer, whimsical.
http://www.cakecentral.com/cake-photo_1344476.html

Thanks! Great suggestions. If there's any others, I'd still love to see them.

here is one i did not much but maybe give you some ideas
http://www.flickr.com/photos/14511451@N05/4889068466/

Lovely! Thanks heaps.

i have a graduation cake I did with a one tier in my photos

You can still look at multi-tiered cakes for inspiration. Just look at the top tier!

I think the biggest display of single-tier whimsical in Cake Central is held by Pish. Small, colorful, whimsical works of art. I love every single one of them. Maybe it will give you some ideas.

http://www.cakecentral.com/cake-decorating-photos-by-pish.html