Two possible (and very similar choices) to put next to your Mitsubishi 55411:
o Mitsubishi's cabinet. I think you want the MR-50705A http://www.mitsubishi-tv.com/accessories.html
o TechCraft Furniture's SF50. I think that's the right
model. It's a kit that looks similar to
the Mitsubishi accessory, but tends to be much cheaper.
I think they go for around $180. SF50 vertical case at http://www.techcraft-furniture.com/htm/products/sculpt/sf50.htm
That's the inside frame, instead of the full web page.
FYI. Good luck in your search.
Jeff