Thread is old - but I'm curious about the same thing (but I don't have an 08-11 Focus).
Some things to help you out.
The base "S" model Focus hast the black face guages and lacked the driver information center. The SE and up had the white face gauges.
On the 2000-2007 you can swap clusters and the only issue is that the TCS or ABS light on the cluster might stay on.
On the 2008-2011, other members have reported that swapping the cluster caused a PATS system error and the car wouldn't start.
I would think it MIGHT be possible to swap the faces from an S to an SEL - keeping the "guts" of the SEL and giving you the best of both worlds, but I'm not sure exactly what would be involved.