Hi:
To get you started try looking at Racks and Stands web site.
May I also suggest the Home Theater sites since some threads post pictures of home theater set ups.

I think you can find some nice shelving to place on either side of the plasma cabinet. It can be open type shelving or you can find groupings that have piers on either side of the cabinet that look like bookcases which looks more like furniture. Both ways can be very nice and functional.

Try Ballard Design,Pottery Barn, and Furniture companies such as Stanley,Hooker,Heckman,Martin,Sligh, and Bernhardt for some options.

There are many companies that make audio shelving I just don't have the names.

Diamond Case is another well designed custom line but they are expensive.
Google Audio Furniture to explore your options.

Good Luck, I found this very challenging when I was searching for a way to house components but I never ended up purchasing the components so my project is on hold.

Been in furniture biz long time, best product out there is BDI all shelves and back are ventilated. Goto bdiusa.com good luck

Try www.salamanderdesigns.com

Keep an eye on costco.com. They sometimes have really nice systems (we have one of their consoles for our LCD flat panel) and the price and quality are usually pretty reasonable.

Personal choice is very subjective, so i will just refer you to a site with many tv stands options with different sizes, colors, designs and etc...

Here is a link that might be useful: Corner TV Console / Corner TV Stands reviews