Finally checked out Auto Boutique (Columbus, OH) after seeing their lot on my commute for months. They keep around 121 vehicles, mostly late-model luxury cars. They were totally fine with my mechanic doing a once-over, which honestly settles half the trust question.
Lot address: 1800 Georgesville Square Dr, Columbus, OH 43228. Visitor parking: Plaza parking at Georgesville. Website: https://www.autoboutiqueohio.com.
Paper side: licensed with the state (looked it up), about 87% of stock has title in hand per the office, and they offer a 30-day/1,000-mile powertrain warranty.
Overall: good people to deal with. 5 years in business around late-model luxury cars, doc fee $399 and it's on the window sheet, no games. I'd send a family member there.