wide tire on thin rim, read cornercarvers.com
I looked at this a while back, based on iskwezm putting 275 on an 8" rim and one other guy with a late model on his avatar, forget right now. What it came down to is this, feel free to correct me with your observations:
-wide tire on skinny rim will work, but what you will feel is a slower turn-in to the turn as the rim moves over the tire. That's the downside, most people want a quick turn-in.
-More rubber on the road means more ultimate traction. Faster launches, more G's around turns.
-If you were in a slalom, you would want wide rims with relatively vertical sidewalls, no bulge - you would be transitioning side to side so much.
Feel free to comment on these observations. I'm not judging, just saying what the benefits and disadvantages are from what I've been reading.