The difference between being roasted and being flamed is two-fold:

1) It lies in the intent of the roaster to have a little fun and encourage some laughter, while not trying to hurt feelings.

2) It lies in the ability of the roastee to laugh along and not get hurt feelings over the comments made.

Therefore, a roast is perfectly feasible IF the person doing the roasting is well-meaning and the person being roasted is agreeable to the process. For example, I point to the "If the mods were in an alliance" thread. A good chunk of those posts were roasting others.

"Wildor has left the alliance." "Wildor has joined the alliance." -teasing Wildor for resigning as a mod, then returning to modship.

"Can I help?" "Is there anything I can help with?" -roasting me for sticking my nose into everything and also refers to a couple private conversations I had with someone.

Heck, most of that thread is a roast. And it was HILARIOUS and taken well by all. That right there is what we'd love to see, although I'm not sure this "roast thread" is the proper process to bring it about.