Urban Collector has some interesting pre-orders up. They have listings for some Thundercats Halloween Costumes. There are three characters currently listed; Lion-O, Panthro and Mumm-Ra. Panthro and Lion-O are available as both Deluxe Costumes and Latex Masks. Mumm-Ra is listed as only a Latex Mask currently. The items are scheduled for release October 2011.
No images or further info has been made available. We will update as new information is released.
Vintage Lion-O Costume Pictured