Howdy Volks.  After going with a rear spare tire carrier, I was pondering
what to do with that available space. I ended up adapting my home made
larger clamshell/tire carrier into a toolbox. I found it handy. Currently I
took it to my machine/Fab shop guys to make a refined design/prototype.
Roughly 27"x 27" the front of it has 45° angles on the sides and  7" tall.
The first quote was $211.  I went downs and verified a few design aspects
including a better sealing surface for the lid and how it fastens down. The
first one/prototype is currently being built. Looking at $211-$250 final
cost from machine shop, I don't know what shipping or anything could be
yet. Hopefully It'll be what I envision and be able to have them available
for those with alternative spare tire carriers. Storage is worth it's
weight in gold, Westy or tin top.