How about instead of just being able to change the time for shots in a game, You could have a list of options and make your own custom game.

This is one of the ideas I've been in favour of for a long time, for both sites.

So long as there was a warning similar to the current rank difference/quick game one, there should be no issues.

"Special Rules" games would, of course, not be included in stats nor be ranked.

Obviously there would still be the warning's for rank difference, and whether it is a quick game or not...

I agree with the
but couldn't you have some sort of a different "stat-game/table" for it;

Example:

Arcade Snooker:
**Insert rank etc etc**

Regular Snooker:
**Insert rank etc etc**

all the way down to carom and then this:

Special Rules:
Rank:"675.00"
etc etc

But have it for a overall rank to rule out any possibilites of "farming" rank... for one particular game type?