If you are able to build from a laser-cut short kit, Pat Tritle has a really nice 54" w/s 172 and a complete build thread on RCG E-Zone Scale Electric forum. His designs are purposely designed as light weight models that can fly at scale-like speeds in fairly confined spaces. This one has flaps, ABS cowl, etc. You can add details like lights, etc., as you see fit and still have scale-like performance. Callie Graphics can make up vinyl graphics that will look just like grandpa's.
http://www.patscustom-models.com/c172_skyhawk.htm