At the risk of sounding sexist, I think the reason a disproportionate number of women take their cars to the dealer is that they have no idea about any aspect of their cars. (To be fair to women, I think most men are the same way.)
And they're convinced that the dealer "really knows" the car --after all they sold it to them!
So I think it requires more than a just a clean facility -- you have to educate them to the reality that they're being ripped off at the dealership.
And for the record, I think your idea is a sound one. You clearly have the business savvy to figure out if it's viable. Just don't overestimate your ability to draw customers -- no product ever "sells itself". And when it comes to getting and holding onto good techs: it's tough to match the pay rate of a dealership when you're undercutting their labor rate by $20/hour.
In case you haven't figured it out -- I've thought long and hard about a very similar concept. I hope you can pull it off. And I'd love to "pick your brain" if you do.
'92 Mercedes 190E/2.3 (247K miles/my daily driver)
'93 Volvo 940 Turbo Wagon (263K miles/a family truckster with spunk)
'99 Kawasaki Concours
'85 Jeep CJ-7 w/ Fisher plow (226K miles)'93 Volvo 940 Turbo Wagon
'53 Willys-Overland Pickup
'85 Honda 750F Interceptor
'93 Nissan Quest
'89 Toyota Camry Wagon
'89 Dodge Raider
'81 Honda CB 750F Super Sport
'88 Toyota Celica
'95 Toyota Tacoma
'74 Honda CB 550F