Phil Johnson still has the max contract offer he can throw in if he gets desperate but I doubt Melo even wants it. Even if LeBron signs back with Miami, they just don't feel championship caliber anymore and they definitely won't be in the long-run unless Napier shows up to all of James' expectations.
There's also still the wild card of Phoenix, they're bound to run off with a marquee agent or two. They have the cap space and decent young talent to sign both James and Melo if they wanted to, and would still have cap space to sign and trade for more. If those two wanted to play together, even though it's unlikely, it could happen at PHX.
If it does, hard bandwagon inc