11: Lab Paint/Decals/Other:  Being able to customize the look of labs with decorations and decals, maybe even paint them, would be neat to see.  Might not be too hard to implement either.

12: Mid-session Requests:  Just something to spice things up a bit.  Have a random chance that a client will make an additional request in the middle of a session, or maybe that clients will ask you to do certain things to please or tease them.

Had another thought.

9: Achievements.  Just so I can get 'now your fucking with portals'.