John -
Check out standard RV suppliers for water pumps.  I installed one 
under the cabinetry (not submerged).  I used a 3 position heater fan 
switch for control and mounted it behind the faucet.  Keep the faucet 
as it is low profile.  Standard RV ones are too tall for the 
sink/stove cover.  Get the lowest flow pump you can find.  RVer's 
have MUCH bigger faucets and tanks than VW's. 
Jeff