The center channel of choice before the 340 was another 170.

And remember, that was before the flat/thin TV boom where you could set your speaker on the TV.

And still, there are not many good choices in center channels with easy mounting solutions. The one you linked to is great, but it is actually a VESA mount meant for TV's and monitors.

I bet though, with some stuff from the hardware store, any speaker with some threaded inserts can be attached to a mount like that.

I wouldn't put any weight on the frame of a LCD screen.