Like the title says:
600 pts Golden Age, 1 fig must be from an Indy set, 200 pts must be from DC, 200 pts must be from Marvel.

My first thoughts was a soldier team with General RAAM. Use him just for fun, but use a green lantern tank (DC75 John Stewart) carrying around 5 or 6 Phalanx Soldiers. Put Trick Shot on the Green Lantern, and also use the new Sgt Rock, to give all the Phalanx willpower.

If I use 5 phalanx, I could also use the Airstrike General Ross for exactly 600 points.

Although I'm for up any ideas. trying to find a good theme (i know my current idea is not one) that can tie across the universes...

Maybe i should go with all figures have to have a bow and arrow, and use a LotR fig...