Yes. I see what you are saying. I've thought about that one many times.
Then I thought about how often I would actually NEED to use it and thought maybe just use the twist on kind for when I have to. Sounds messy though.
I've been trying to find a price on this one.
http://www.thetford.com/wp-content/u...SaniCon-II.pdf
Depending on the price, I think I can make it work and have it hidden behind the frame in the area of where the drop frame is.
Next plan was the one pictured above by Dan..I can't find that anywhere either.
Had I of had the option in 2016 I would have gotten it.
Can you show a picture of your the door you found on eBay?