My Hitachi 51F500 had a wide enough top to support my VP-100 center speaker, but my replacement t.v., the 51F520 is MUCH more narrow on top and cannot support the speaker.

I know they makespecial plates/stands for this purpose...where do I get such a thing, and will it fit my t.v.?

Maybe this thread will help.

Something like a small tv swivel mount may work as well, they come in a variety of sizes.

TV Mount