Back in the early 90's when I lived in L.A. there was a company
called Pacific Woodworks that built guitar cabs and they made a
2x12 vertical cab that actually sounded pretty good. The bottom
half was a closed back design that looked alot like a EV TL112
speaker cab design on it's side and the top half had the angle
design and was open back....It seemed to be pretty popular with
some of the session players out there as well....
The draw back to a smaller 2x12 design is that you can still
run you amp or rack into it and it will usually handle the wattage,but
you're trying to make 2 speakers do the output coverage of 4,and
alot of times it just don't cut it.....It's going to sound thinner and
not have the 4x12 thump that we're use to hearing .........
Try ebay- I seen some of these cabs on there before.....