You could gather the rest of Bruce Jones' Vertigo work that's appeared in some of the genre miniseries like Weird War/Western Tales, Flinch or Strange Adventures. Or if you want to combine other updated/revised takes on older characters, there's the 6-issue Beware the Creeper (with fantastic art by Cliff Chiang), the Sandman Mystery Theater: Sleep of Reason (although it does have ties to the original SMT) or the 16-issue Kid Eternity (probably fits the best with Deadman and would be a nice size).

I agree, though, that 13 issues isn't too bad for a binding. While I generally like thicker books as well, if there's nothing that necessarily fits, I wouldn't add stuff just to have a bigger book. My Midnight, Mass book collected the 2 minis and was only 14 issues. I combined Loveless and El Diablo just because they're by the same team and still have the Western motif. I made a huge Omnibus collecting all the Vertigo genre minis. Then there are my writer-centered books (Jamie Delano, Peter Milligan) that collect all their Vertigo works.