Idol-Head reader Tom Hartley submitted his above mock-up cover for a highly unlikely third Showcase edition. It's based on Luke McDonnell's cover for Justice League of America #248 (3/1986), and he offers an alternate Chuck Patton cover here from J'Onn's final confrontation with The Marshal! Tom also offered his choice of reprints for the hypothetical volume:
Even though a Vol. 3 probably won't happen, I've been thinking about what the contents would be. Here's what I've come up with:
Justice League of America #71
World's Finest Comics #212
Justice League of America #115
Adventure Comics #449-451
World's Finest Comics #245
Justice League of America #144, 177, 178
DC Comics Presents #27
Detective Comics #500
Justice League of America #228-230, 248
Action Comics #595
Martian Manhunter #1-4
Secret Origins #35
Martian Manhunter: American Secrets #1-3
That would be 575 pages of material. I know American Secrets deserves to be reprinted in color, and in hardcover, but a black & white reprint would be better than nothing.
I'd throw JLofA #200 into the mix, but take out #248, since the John/Gypsy subplot dragged on for months. In fact, it even merged with a separate Zatanna subplot which preceded and overwhelmed Manhunter's. You'd have to include pages from #249, #255, #256, and #257, but in the end it still wouldn't make much sense. I'd also want to see 1987's Justice League Annual #1 and "The Man I Never Was" from the '89 JLI Annual, as well.
However, this is all pie in the sky business. As explained by Bob Greenberger, "DC pays a royalty based on a percentage of the cover price to writers, pencillers,and inkers to all material published prior to 1976 and after 1997. For the period in between, the vouchers that were in use called for a set reprint fee to be paid. In some cases, the amount of contractually obligated reprint fees makes the budget for a proposed collection unprofitable." Creators have the option of waving the set fee, but just tracking down and negotiating with everyone involved (or their estates) in the issues Tom suggested would be a Herculean effort no one's going to make for the Martian Manhunter.
On the plus side, Volume Two was finally released this month, so you can thrill to every confrontation with the magnificent Professor Arnold Hugo, every emission of the Diabolu Idol-Head, plus the first appearances of Zook, Marco Xavier, Mr.V/Faceless, Vulture and many more!