We bought and I installed a new cup holder because base units come equiped with the storage tray. My wife used it once with a paper cup (Chick Filet) in which it promptly punched a hole in it. She's never has mention about using it again. I use it occasionally but with plastic bottles or cans, but I find it in inconvient to reach and it often rides in my lap or hand.
IMO, get the storage bin, forget the sliding unit idea, (you might have to change the center console), and apply the KISS method. Offer me a $150 plus and I'll remove cup holder and send it to you.