I got this drink holder that you can flush mount. I fabricated a bracket with slots to mount it to that I could attach to the square tubing behind the dash. I slotted it to allow for adjustment so it would mount flush with the lower dash panel.
I mounted the assembly then measured and cut my lower panels. Then I covered them in leather and you will see in the pics how the idea works
If you have a large drink in it the passenger a/c vent gets blocked some what but I have console vents to make up for it. Besides, the a/c blows so strong, you probably would not notice it that much anyway.