I have a similar situation. everyone makes 30"
models but 27" are in short supply, not to mention
the prices are absurd for what you get.
My advice is to enlarge the opening, even if it
is made of stone, nothing is impossible with the
right tools. That's what I plan to do. I'm tired
of searching for a non-existent product, when you
can get it in the 30" version for much less.