SOS all the way guys.
People really just need to learn how to set up their guitars properly. I use vintage type trems and my tuning is fine for hours of light trem work. Often times I will try to make my vintage type strats go out of tune with the trem, and I can't. I use all 5 springs and 11's though, not sure if that makes a difference. Great workout though. LOL
Where you run into problems is with too many contact points. The only reason floyd's stay in tune is because you have only two contact points and only two studs. On a vintage strat, you simply back off the four inner screws a couple of turns, lubricate all 6 screws, lubricate the saddles (and make sure they have no burrs), lubricate the nut (make sure its properly cut), lubricate any string trees you might have (or go with Sperzel staggered height tuners and eliminate the trees, I think they are one of the worst offenders in throwing a vintage type strat out of tune!) and you won't have any tuning problems.