It was difficult.
Let's assume that because the Knicks are 1-3 and just lost to Charlotte and Tyson Chandler may be hurt, James Dolan is going insane and has a puppet GM who will do what he pleases. This isn't a baseless assumption.
And also assume they don't have any assets to deal, outside of (I suppose) Iman Shumpert. So there only leverage is the ability to absorb huge contracts. The problem there is that they have no real expiring deals: Bargnani has an ETO this summer which could maybe be banked on but who knows with that guy. The big one expiring the following year is Amare Stoudemire, which is this year $21.7m, and next year $23.4m. Poor Amare just can't play anymore, which is sad.
(as a reminder, they can't amnesty Amare, already used theirs. Another team can't acquire him and use it either)
The league is getting a bit smarter and restricted by the CBA so there aren't quite as many bad longer-term deals out there. But I think there's one team that might be interested in dumping such deals on the Knicks and just having Amare sit on their roster.
That's the Celtics. Due to them going all-in in the 2012 offseason and it backfiring, even after the Garnett/Pierce trade they still have a lot of big contracts they don't want.
3 years remaining (including this one):
Gerald Wallace - $10.1m/$10.1/$10.1
2 years remaining:
Brandon Bass - $6.45/$6.9
The Celtics don't really want these guys (to varying degree) and there are many combinations to acquire Stoudemire's 2 years remaining, and just buy him out or rehab him. Frees up playing time and future cap room. And the Knicks alleviate some roster issues without actually having to give up an asset (which they don't have anyway).
I think Wallace+Lee+Humphries is the least complicated deal, though it'd have to wait until December when the Knicks can send some of their minimum-signings back in the trade. The Celtics have a lot of low-firsts owed to them, maybe they'd actually spend one to get those Wallace+Lee 2016 years off their books. Maybe the Knicks like Bass instead of Humphries...there are a lot of combinations.
This doesn't put the Knicks over the top or anything, and even makes their financial situation a bit worse, but again I'm assuming Dolan doesn't care about that and just wants a quick 'fix'
Melo/Wallace (they'd go small a lot you'd think)