That's the question. DC has never reprinted this (that you know of) in color (so the Showcase collections don't count) in any form. Trade, Omnibus, any kind of anthology.
To start, I'd love to see an omnibus collecting all the DC adventure stories (I can skip the humor and funny animals) from the 1930's (beginning at the beginning in 1935), excluding Superman & Batman, which we've already had.