The closest I've come to that is my SpAAT frame.
It's built using the Hallowe'en Spiders and Star Wars AAT polybag sets. (And a few extra pieces. Sshhh, don't tell anyone.)
With Memorial Day and the long weekend coming up here in the States, I'd like to propose a little challenge. Pick a small to medium size set, it can be any set old or current, and build any number of mechs from that set. You don't have to use all the parts but you have to use only those parts in the set. To keep things fair, I say everyone goes by the Bricklink Catalog set lists. You can do this "in the brick", on LDD, LDraw, or any old way you can manage put some bricks together. You can post a link to your results in the Comments section of this page. You can also post a picture to the Flickr group, the Hangar forums, or the Facebook group as I'll be cross-posting this challenge to those sites as well.
I look forward to seeing what people build.