Wiper switch configuration

[Joe <jw@mitre.org>]

I'm replacing my dash, and putting in new switches for my lights and
wiper. Using standard switch nomenclature, the light switch seems to be
a SPDT Center Off. The wiper seems to be a bit different, there are 4
wires coming to it, and the diagram shows a fifth terminal going to
ground. Is there a more or less standard switch that will replace this? 

I bought 5 feet of solid walnut and plan to make a one piece dash,
rather than 3. Does anyone know of any special problems with this idea?

TIA
Joe