Speaking of tops, has anyone replaced or considered replacing the canvas portion 
of the poptop with one of the many breathable/waterproof synthetics (GoreTex 
nylon, etc.) used in modern tents?

The notion intrigues me because here in our neck of the woods (PNW), there is no 
such thing as dry weather camping. Even in summer, dew will dampen the canvas to 
the extent that I am loathe to close it for fear of mildew. Spray-on water 
repellents help a bit, but not when the rain is coming horizontal to the bus at 
30 mph, or falling straight for more than a few hours. I've found it necessary 
to use a rain fly (tarp) over the pop top to keep the upper bunk habitable.   

Needless to say, this is annoying.

There's a fabric store here that sells all flavors of high-tech outdoor fabric 
and if I remember correctly, the Bently manual takes you through the the process 
of replacing the canvas.

Anyone else put thought into this?

Paul