It's unusual to find character LCD's larger then 20x4 because the most common LCD control chips can support only 80 characters. For larger displays they sometimes use two controller chips on one LCD making 40x4 a fairly common size.
This company sells 40x4 TTL serial LCDs:
http://www.matrixorbital.com/p119/LK404-25/product_info.html
http://www.matrixorbital.ca/manuals/LK_Series/LK404-25/LK404-25_rev_20.pdf