The Wii documentation said NOT to locate the sensor bar on a shelf on the stand under the TV, but since it wouldn't hurt anything, I tried it, works great!
It's also unnoticeable - it's sitting just in front of our DTV box and DVD player (the player drawer actually opens +over+ it ). I used the little clear stand to give it a little more height.
Umm, to (poorly) illustrate the arrangement:
[*****] < TV
-------- < Top of Stand
--+++-- < First shelf of stand, +++ = sensor bar
-------- < Second shelf with PS2 and Wii
-------- < Bottom Amp, Preamp
The shelf it about an knee height, so it's fairly LOW, but it works sitting in the room 10+ feet away, or standing to one side (like for bowling).
Hope that helps (and you enjoyed my ascii art )