Well I just tried. Interesting results.
I have got skype and cheese and webcam toy and hangouts (which all do work) and tried them together.
You can't use the same webcam on 2 things at once.
Cheese (Working) + Webcam Toy (Not working) + Skype (Small, top right. Not working).
You can use 2 webcams on 2 things though. (Cheese + Webcam Toy).
Hangouts (Not working) + Cheese (Working)
Hangouts (Working on it's own).
Cheese broken when I opened Hangouts first. It did the same with the others, but my internet is too slow to upload every single screenshot (and I doubt you'd appreciate 30+ screenshots)...
I even tried making a symbolic link to
/dev/video0 and saving it in
video2. That didn't work.
I also can't run 2 cheese processes at once.
A picture of my garden, to cheer you up, as the answer is no. It is very cool at the moment: I can swing (on the swing) and jump off and land in the paddling pool. Taken with cheese.
If you had to, I would advise making it full screen and doing 2 screen recordings. I doubt that would work for what you want though.