🚀 go-pugleaf

Yes, I've hacked it to do something like this (I needed two up
format in a similar but different way).  In the postscript
prolog (pscat.pro or psdit.pro) you can hack the macros that
the formatter puts out to begin and output pages.  In pscat.pro
it's BP and EP, and in psdit.pro it looks a little more complicated
PE, PB and p.  What I did (for pscat) was to put a translate and
scale in the BP macro (superseding what was already in there) that
depended on a boolean that flipped on every page.  In EP the boolean
gets flipped and if you've done both halves of the page executes
a showpage.

-Ron