The background must be your creation just use some brushes to get it interesting.
Model pics and generally pics for the use of photoshop for signature and in general art creation are called renders and you can search for them throughout google or www.planetrenders.net
about the fonts you can use http://refont.com/ they have many fonts for you to use as for the brushes you can hit www.devinatart.com.
Also in order to get your signatures draw attention you should use C4D renders.(You can find those in planetrenders.net as well as to some other places of your choosing)

Hope i helped a bit
Cya around