I believe the limit is six. I installed the clock applet and my BT KB icon disappeared. This may be deeply rooted in the interface, if you look at the documentation talking about how they sliced up the interface it seemed to be very specific.

Now what I'd LIKE, is to get rid of the default ones (ie brightness/contrast and sound volume). Those could easily be put under the app menu.

Also, I don't even have a cell phone much less a BT enabled one with a dataplan. That X'd out phone is looking pretty tiresome.