"If there were a change in the law on MLP taxation would it permit the MLP to continue as a tax paying partnership or require the equivalent of a conversion to a C corporation? Could the assets be transferred to a corporation in a tax free transaction?"
Nobody could possibly answer this as it would depend on how the legislation was written. There's little point in indulging in guessing games.
As for your earlier comment:
"This threat continues to arise in the media and from government sources."
I believe there is little about this coming from government sources. What rumors there have been have mostly come from the media, hedge funds looking to take advantage, etc.
The debt supercommittee has said nothing publicly, but who knows what they are discussing in private.