yea I kind of forgot this is specified BJJ thread, which I guess I cant say much as most of the things that I've known and encountered from BJJ are ground oriented. At school the club hasnt done (not sure if they will) randori from stand up, it always starts on the knees. So hard to say.
In terms of slams, the best kinds would be the ones where you dont fall down with the guy. But you would have to move around to gain yourself a good position (in terms of the guy and his buddies) in order to do so. Aikido randori would probably be the best thing to describe it. But like you said, this isnt about Aikido, its BJJ.
But Mr. AndrewGreen here brings up the point that BJJ (and grapplers) train for take downs and take down defense, while their kungfu counterparts do not train in either one. And in order to score your take down you must also learn to pass the strikes or guard of your opponent. And though it pains me to use him as an example, Royce Gracie has demonstrated that he learned to pass a striker's guard to get the take down many times. And once the grappling starts, I believe the grappler has the advantage.
So its either 2 choices: learn grappling or be really quick with your feet and hands to avoid or strike the grappler down before he clinches up with you.
"you're going to work till you wish you were dead and then keep going.."