Just because a sealant has a recommended full-cure time of 12 hrs doesn't mean you can't drive it. It's not like the coating is gonna fly off as you drive down the road. The full-cure time is mfg recommendation to fully cross-link for re-coat and before getting it wet. And, like Mark said, you can always go with an accelerated product like DG, or even one of the new "super coatings" like CQ or OC.
Also be aware that mfg recommendations tend to be very conservative. Mfgs use recommends to dissaude people from abusing the product and application. Sealants are probably pretty well cured in half the time stated by the mfg. I've had my car get hit by a sudden thuderstorm like 4-5 hours after application with no ill effects.