I am not sure of this, but I have two mining rigs and I thought that it may be beneficial to put them both on the same worker from my pool.
Is this possible and if so what would be the benefits and/or disadvantages of it?
I wouldn't although I don't think you'll have any problems. Creating a new worker is quite easy. All you'll have to do is copy past your .bat file CG miner into a new CGminer folder, open it with notepad, change your username and password to the new worker - U and - P and keep all other settings the same (if you're using the same GPU models obviously).
Quite easy. Here is an example of a config I could use on another PC for a 7870:
color 20
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
cgminer --scrypt -o stratum+tcp://mining.usa.hypernova.pw:3333 -u xxxx -p xxxxx --shaders 1280 --thread-concurrency 16000 --intensity 19 -g 1 -w 256
Sorry if I overexplained things. Hopefully this help's answer your question.
you can. i've done it several times....