After 25 years I finally found the perfect holder to accomodate the big Starbucks ice tea glasses and coffee thermo-mugs my wife likes. Probably not for everyone, but......

I was in Walmart looking over the cheapie cup holders just for ideas, and I found a little flexible "cup" from Rubbermaid made from really nice, thick black rip-stop nylon, like the high-end Tumi luggage. Designed as a cell phone/sunglass holder, It has a fairly rigid top, and a little loop to attach it. I basically set it on the floor in front of the passenger seat, and attached it to the side of the center console carpeting with a couple of chrome sheet-metal screws. Zero permanent impact if I ever want to remove it.
Sounds hokey, but is virtually unnoticeable down there, zero interference with the passenger legs/feet, and very easily reachable by the driver. Holds everything from a coffee thermo-mug to a big gulp perfectly. She's so happy with it, I got another one to put in the Caddy Wagon.

DG