Hey Bert - Do you mean such a beast like e.g. Mani has ?
Something like that but smaller will do as well as long as you do not connect all your PC's to that one transformer... ;-)
I am using a 1000VA for both my PC's (and related switching adapters), one monitor and one Behringer.
http://www.amplimo.com/index.php/products/safety-transformers-for-medical-use
Bert