Home/auto Steam Cleaner or Wet/dry Vac? Recommendations?

You say cost doesn't matter.... after going through a few different Bissell models over the years (we've had cats for 19 years and kids for 14 now), last year we bought a Vapor Clean. It cost quite a bit more, but we've found we don't need to use chemicals any more! There is a place for them if needed, but it's truly a steam cleaner that heats water so hot that it really makes steam! My husband did the research and since he's the one who's willing to steam clean, I let him pay for a much better model this time. He's much happier with this machine than any of the others. http://www.myvaporclean.com/vapor.htm

Rent it to the neighbors!
I suggest you go to an old fashioned vacuum cleaner store/repair shop - they can give you great information and have seen which brands come in for repairs the most. My BFF went through 2 Bissell steam cleaners ( the kind for carpet) before switching to a Hoover. The Bissel is notorious for wearing out right after the warranty is up.
Check consumer reports too. www.consumerreports.org

We tried the Bissel from Costco and returned it - twice. Do not buy a Bissel.

We are planning to just suck it up and buy the industrial one there for $500. We have kids, dogs, and white carpet (that came with the house)! I am not sure if it would work for your car, but Costco is just awesome about returns, so we try to buy there for things like this.