Of late, I've thought a Toyman story which used licensed properties would be a rather good idea. Superman vs. Transformers, G.I. Joe, Micronauts, AT-AT imperial walkers, Gundams of all stripes, and beyond.
I shudder to think of the licensing issues involved there. In comics, it would very difficult, since those properties are all licensed to different publishers than DC. (Although if Toyman had been a Marvel character back in the '80s, the first four would've been easily doable.) In movies, maybe the Micronauts and Gundam could be licensed, but the screen rights to Transformers
and GI Joe
lie with Paramount (and Dreamworks in the former case) and Star Wars
is Lucasfilm, so they'd be unlikely to show up in a WB-produced Superman film. (On the other hand, The Clone Wars
airs on the WB-owned Cartoon Network, so maybe something could be arranged there.)