I think another possibility that hasnt been mentioned for Howard is a sign and trade. Orlando offers Howard 'crazy' money, (which they can do) and he takes it with a deal on the table to a team of his choice. That completely negates the cap room argument and would only be unlikely if Howard thought the team he joined gave up too much to get him.
A team with talented young players, stockpiled draft picks and a solid core could be very attractive. Portland, OKC, Phoenix, Chicago, even the Hawks could make something out of that scenario just to name a couple.