Koyote,
I have three wireless mic receivers as well as a mixer that they all converge into.
When I use my small rig, the Fender Passport (and don't have my mixing board) I need something that can stand right by the Fender to plug everything in from.
For that purpose I use a CHROME rack that I got from a store like "Bed Bath & Beyond". It is designed to hold/mount 3 baskets. It weighs but a couple of pounds. It is 31" high. It is 11" wide and 8" deep.
It is important to note that in order to make this work I inverted the baskets, tying them down with wire to the rack. So... I ended up with three shelves, each of which can accommodate 2 receivers. I had as many as 3 receivers and my mixer on the rack.
When my wife is up and around later today, I'll have her take a picture of it and forward it.
One last important point which you won't see in the picture. When I use the rack I attach a surge strip to it and plug all of my transformers into that strip before I leave for my show. That way, when I get to the show I just have to plug the strip in and from the strip I plug in the transformers for each receiver.
As for those of you who ARE actually looking for an "expanded" mic mounts... Sam Ash offers this:
It will handle up to six mics. I have seem it in person and have ordered one of them
http://www.samash.com/webapp/wcs/stores/servlet/product_MY700%20Multi%20Purpose%20Stereo%20Microphone%20Mounting%20Bar_-1_10052_10002_-49968724_cmCategorySA-10001
If you just need a mount for two mics this, which I already have, will do the job!
http://www.samash.com/webapp/wcs/stores/servlet/product_MY500%20Stereo%20Microphone%20Attachment%20Bar_-1_10052_10002_-49972356_cmCategorySA-10001
If you want three mics on the stand, just add this clip-on to the dual mount stereo top. I do that from time to time and it works fine! I also clip the thing on the table by me if I want to have a hands-free mic of my own.
http://www.samash.com/webapp/wcs/stores/servlet/product_HM12DC%20Gooseneck%20with%20Spring%20Loaded%20Clip_-1_10052_10002_-49995419_cmCategorySA-10001
I believe they also have access to getting custom made mounts.