This has to be one of the coolest Transformers Costumes I have ever seen. This Bumblebee costume was created by Lionel Lum for Comic Con 2008. He says that it took him 3 months to design and build. The costume is made out of "foamboard, hobby foam, vinyl signage applique, and is held together with tons of hot glue and some duct tape here and there."
He spent 8 hours a day in the suit during the con, and claims it only takes 10 minutes to put on and 5 minutes to remove.