I'd go with the Raritan PH II or PHC (same pump, but on a compact base and with a shorter handle to fit in a tighter space). http://www.raritaneng.com/products/toilets/index.html Which one depends on how tight your space is. And Raritan has come up with a way to make either one a LOT more affordable. Check this out: http://shop.sailboatowners.com/detail.htm?group=1357&cat=1002