The LEGO Star Wars Ultimate Collector Series sets have always been great. But at the same time they've mostly focused on the BIG starships, and I think it would be cool for them to do some of the smaller vehicles. They could of course do Luke's Landspeeder from A New Hope, but I think a cooler vehicle would be the Speeder Bikes from Return of the Jedi.
I made this set in LEGO Digital Designer awhile ago, and it was just under 300 pieces. I used dark gray because the pieces I needed weren't available in brown. I think with some of the newer official colors and pieces available (curved slopes, etc.) LEGO could make an awesome UCS Speeder Bike with nice greebly details that's a lot more accurate to the movie model than the minifig versions of the bike are able to get.
Plus the thing looks cool and with a stand would take up considerable less space when displayed on a desk or shelf compared to the recent large UCS sets like the B-Wing and latest X-Wing.
UPDATE: I re-colored the bike with brown pieces (a few dark gray are left, mostly in the cracks and underside, for added depth & detail.) And for anyone who's curious, the model is about 12" long (around 40 to 42 studs in length.)
UPDATE 6-11-13: I added a new POV RAY render of the model for the main image. Thanks brickmania4u for the suggestion.