Any replaced materials to be consider for trolley?

My concept is to design book trolley for the customers.
Any suggestions for the material? Other than stainless steel.
Could it replace by environmentally-friendly materials? Durablity has to be consider too.

Thanks. (;

Just so we are clear on your definition of Book Trolley, you mean a cart, with which, to move books. Yes?

i.e.

As opposed to a mobile library, aka: Book Mobile

If so, check out a few …

http://images.google.com/images?sourceid=navclient&ie=UTF-8&rls=GGLR,GGLR:2006-18,GGLR:en&q=book+trolley&um=1&sa=N&tab=wi