You want a seaplane like the Seamaster, but don't just want to pour glue into an arf box, shake it, and have an airplane fall out?

How about Plans-building an A-Hoy? It's a Chuck Cunningham design published in RCM probably 12-13 years ago. Seamasters are 40- or 1.20 size: the A-HOY is a .60 size plane.

http://www.skymaster.net/ahoyplan.html