After the current finals I'd suggest the following trade between the Knicks and the Cavs.
Cavs receive: Melo
Knicks receive: Iman Shumpert, Channing Frye, Richard Jefferson, The Cavs 2020 1rst round pick and the right to swap 1rst round picks in 2021 (both unprotected)
If Melo drops his no trade clause the trade works under the CBA.
Why it works for the Cavs: They don't give up much (now) and with Melo they get another scoring option from the bench. Lebron can get more rest and their bench will be far more competitive.
Why it works for the Knicks: Shumpert might be a keeper but the real deal are the first rounders in 2020 and 2021 (swap). At that time the Cavs will probably be a lottery team. Lebron will be 35/36 and will probably either play for another team or retire until then. The Cavs will be quite saturated and really don't have many options to improve their team until then.
Why it works for Melo: He has a chance to get to the finals and maybe even win a ring. Additionally he could work with his friend Lebron.
I know that this will take patience for the Knicks. A thing that they normally don't have. But this may pan out as a Boston - Nets scenario. Getting unexpectedly high draft picks while hopefully being a playoff team. To sweeten the deal for the Knicks some 2nd round picks or even the 2012 first rounder could also be included.