The Compendium format would be a good option to publish complete runs in a few volumes. So far, DC is using them for Vertigo or non-standard superhero fare (eg Robinson's Starman), but there's no reason they couldn't branch out into other titles.
And if DC wants to keep the Compendium brand for the more serious or mature books, they could use the same format and just come up with a different branding, eg All-Star Sagas. (If anyone from DC is reading this, you can have that for free.)