Do they need one?
Can you build a pocket-sized pistol with Glock reliability/simplicity/design?
Doubtful. If you could, they'd have built it for now.
The closest answer is a Kahr... Similar, but admittedly not as reliable.
If Glock (Springer/Sig/etc) built a pocket sized 9mm, they'd sell faster than they could ship them. I'd be second in line, right after Mike Barham.