I think we should be careful here. For starters, how much extra capacity can we really fill? Are there really 1000s of additional fans out there or is this just hand-waving and wishful thinking?
Any development of SB as outlined by any of the options above will not be cheap. Which would you rather have - a shiny, brand-new 25-goal a season striker - or spend (waves hands himself) £2 million on a temporary stand that will be redundant if we do move grounds?
That stand may well "pay for itself" in a few seasons, but the bank-balance would still be down by a significant portion of our (cliche alert!) war-chest.