I'm not aware of any such Perl bindings, but I've to admit, I haven't searched hard enough. Calling gphoto2 for a Perl program (and having itself call another one using --hook-script) does the job for me.

And calling external programs from Perl is actually very Perlish; Perl, after all, is a glue language. And since most of what you want to do with gphoto2 is I/O bound, the overhead of calling another program is insignificant.