i dont thiink so pstanley. teh sweeper corals are modifications of teh regular bubble, but your coral cant just change them into sweepers. usually sweeper tent have stinging cells called nematocysts, where as the normal polyp doesnt. a lot of times corals keep their sweepers hidden during they day, but expose them at night as they are gettign a stimulation to feed, this is why if you look at a bubble coral during the day, you see bubbles, but if you look at the same coral at night, the water is transferred from the bubbles to the tent, and the bubbles are very miniscule.
memnoch, i have never heard of anyone cuttign off the sweeper tentacles of a coral. its not a dumb question but definately an intriguing one. i would just imaging that the excision of a part of any coral would cause that coral reasonable amount of stress, and you could possibly lose it, which is never a fun thing. definately an interesting thought though
good luck
jon