Sony Ericsson Robyn was just leaked earlier today, and it's the next upcoming Android phone from Sony Ericsson. It's a very small handset with a design similar to the X10.  My guess is that it's targeting the lower end of the market than the Xperia X10.

It seems it'll be available in three or four different colour variants, as you can see from the different back colours. Specifications include a touch screen, 5-megapixel camera with autofocus, 3.5 mm audio jack, USB connector, HSPA, WLAN.

via: SE-Blog.com