I've never used wireless mice or keyboards before and need to learn how
reliable they are when used in "proximity" to a small form factor PC that
will be mounted "behind" a HDTV mounted to a wall. I'm planning to put the
keyboard and mouse in a box mounted to the wall just below the HDTV hung on
the wall inches above. When the lid of the box is opened it will swing down
like a tray holding the keyboard and mouse but I don't know if this will be
allow the keyboard and mouse to operate?

How would Microsoft's wireless keyboard and mice work then? I'll continue to
do some looking around but any help to determine how these things actually
work so I can know the range and limits will be very helpful to me thank
you...