Found this
https://jazzsales.com/product/holdin...ter-end-drain/
NOTE: reading the description, the lid is glued on.
These have been known to fail (Lid separating from tank).
You are better off finding a "rotoplast" (one piece molded) tank.
Any chance you could fit a bigger tank in that space. If I was doing it I would try to find a bigger tank if possible.