Clone to your hearts content. Your VM SIDs can be the same.

I was bought up believing machine SIDs must be different or the world would end one day.  No one new why or when but it obviously would.  If all your machines have the same SID it is just asking for trouble right?  Well no.  It turns out it is actually not a problem at all.  But don't take my word for it.  This chap really knows what he's talking about.

I've posted this item because I've read it before but I always fret about cloning things for no good reason.

http://blogs.technet.com/b/markrussinovich/archive/2009/11/03/3291024.aspx