If I have understood the cap rules correctly (which certainly may not be the case, though I tried to find the best info I could), here's a scenario that I think could have worked under the rules. You'll probably see why not all three teams could agree, though there might have been some initial interest:
Cleveland must first clear Shumpert (ie into cap space somewhere, or perhaps for Diaw, who could then be renounced), and basically renounce all their non-guaranteeds, then:
Cleveland trades: Irving, Thompson, Frye
Cleveland receives: Paul George, George Hill, Favors
Utah trades: Favors, George Hill (loses chance to sign), Dante Exum, picks
Utah receives: Irving, Frye
Indiana trades: Paul George
Indiana receives Exum, Thompson (two top-5 picks still 25 or under), plus whatever Utah picks are agreed to
You can probably see some of the potential hangups with this sort of deal; the biggest is that Cleveland would be stuck with a bunch of minimum deals after their top seven, though that top seven would be really strong and flexible (if health held up):
Lebron
Paul George
Kevin Love
George Hill
Derrick Favors
JR Smith
Richard Jefferson
Anyway, a dead issue now ...