I recently purchased an '09 Liftback, and so far I'm really enjoying it. However, one thing that has bothered me since day 1 is how small all the cup holders are. I usually drink out of 1 Liter bottles and cups, and it was a pain trying to figure out where to put them.
Well, one day I came across this on ebay:
Foldable Black Drink Holder
I knew exactly where to put it that would give me easy access to my drink, be somewhat out of the way of things, and would cover up some velcro that the previous owner had glued to the piece where I knew would be the perfect spot for this drink holder.
I've had it for about a month now, and it is holding up very well. It holds my drinks well, and I can fold it up when not in use.
I'd imagine if you don't want to drill into the plastic panel, you could instead mount the cup holder with industrial strength tape. I couldn't get the velcro off that is behind mine that the previous owner had glued to the plastic piece, so I didn't mind drilling a few screws into it. I know it will be secure too. I suppose I also could have just attached velcro to the cup holder and simply used that with the velcro that was already on the plastic panel. I didn't know how well that would hold, so I decided to just put a few screws in.