I have a 32 gal "Tote-N-Stor" tank that's shallow enough to just fit just under the sewer discharge outlet on my E19 (no axle lift) . I only use it to drain the grey tank and don't utilize a sewer hose. I fill the the tote with a 45deg elbow attached directly to the outlet. The elbow slips inside tote inlet by about 1/2".
There might enough height difference to use a shortened standard sewer hose with an accordion-style support....but I have not tried. If I had to drain the black tank into the tote with my current set-up, I'd be inclined to use a 12v macerator pump that attaches directly to the sewer outlet.
This tote tank was given to me by an acquaintance, so I don't know how easy it is to find new. It's definitely lower in profile than the Rhino branded tank I was looking at prior....
https://canadawidervparts.com/produc...allon-capacity