just read this today & had to respond. I've always been wondering how I could be the only one who needed a monitor with two bases :) unfortunately, they are hard to find. I don't know why, because it has always seemed to me that instead of 2 parent units & 1 child unit, all monitors should have 2 child units & 1 parent handset. I can carry the parent unit around as I go about household duties, but I don't want to have to move the child unit every time I want to give baby a change of scenery. plus, if you have two young kids in seperate bedrooms, it's nice to be able to hear both of them.
a few years back when I was looking for the same thing I got lucky. I found one that has 2 parent units & 3 child units to monitor 3 areas of your home at the same time- it has been great! but since then, I have never seen it in the stores. the one I have was made by 'safety 1st'. it is called the Home Connection Monitor System, item # 08038. I did a quick google for it before writing this & it looks like they don't sell it anymore.
I think if you do some internet searching for multi child or multi room baby monitors you can find a couple. Some names that I saw were 'Graco Baby iMonitor Multi Child Multi Room Baby Monitor'- and on amazon.com 'Summer Infant Secure Sounds Digital Multi Room Monitor'.
good luck!!