Miami would need to either dump Beasley or each "star" would need to start at less than the max for them to team up in Miami.
Assuming they dump Beasley, and can get the big 3, the team looks like:
Chalmers
Wade
LeBron/Butler(2)/Williams(2)
Bosh/Varnado(2)
Pittman(2)
(2) indicates 2010 2nd round picks.
That team has a LOT of holes in it. No real low post presence, no 3 pt shooting, no depth.
The big 3 in Boston were great, but they also had talent like Perkins at Center (Not a great offensive talent, but a defensive presence) and Rondo as a developing star at the PG spot. They also had niche role-players like Eddie House and others when they won the chip.
The Heat would need to get really lucky and have some good vets take the minimum for them to fill out the roster.
That said, I'm sure it would either work amazingly, or end up as the most pleasant disaster to watch. Either way, would be fun.