I was trying to come up with a reasonable trade scenario and I came up with something like this
Boston - Irving, Zeller, Gee (for dollars)
Lakers - Rondo
Cleveland - Sullinger, Green, LA 2014 player (Smart, Exum, etc.), Boston 2015 1st (lottery protected) or LAC 1st and Boston 2015 2nd (if Boston 1st is in lottery)
Obviously Irving needs to sign the extension, but I think this is the sort of trade that would make sense for all three teams. The Lakers would need to do the trade when they had cap room as their rookie's salary is way less than Rondo.
I'm not sure I do the trade if I'm Boston, but I think that is the sort of trade that it would take to get a newly extended Irving.
If you make the trade Boston would like this (after re-signing Bradley, Bayless, and Hump):
PG - Irving, Bayless, Pressey
SG - Bradley, ?, Johnson
SF - 2014 rookie (TJ Warren?), Wallace
PF - 2014 rookie (Julius Randle?), Olynyk, Bass
C - Humphries, Zeller, Faverani, Anthony
Depending on the rookies (nbadraft.net has Boston taking PF Julius Randle at 4 and SF TJ Warren at 17), I think that team might develop into a real contender in a season or two.