I drive 740's all the time and the best solution to the cup holder that I found is at WAL-MART for about $3 you get 4 (count 'em four) plastic cup holders in a choice of colors that are made to clip on the door panel. BUT they don't fit the door panel on a 7 series, they DO fit on the glove box door. You can even line three of them up there if you want. They will hold a big cup and since I use an insulated cup that keeps my brew warm or cold on the long hauls it is my favorite fix.
The ones that come from the dealer (on the console cover) will not hold anything bigger than a 12 drink can and the one that IPD has on the door gets bumped when you stear around mountain curves and spill when you slam the door. The only problem with the glove box mount is the acess to the the glove box during use. And I still like to keep the center counsole for tapes and CD's.