libpq and multiple selects in a single query

I was musing a bit today, so don't take this to seriously...

Would it be worth the effort to add to and/or modify the libpq API so
that multiple selects could be sent to the server in a single request
and response? Obviously, this is trivial from the command line...

select * from foo; select * from bar;

But - at least as far as I understand the libpq API - only one select
can be issued using PQexec.

In many of the apps I develop, I find that the majority of the time I
have to go to the database for a select, I have to select from several
tables. I haven't done any benchmarking, but given the rule-of-thumb
that inter-process communication incurs high overhead, I decided that
being able to issue several statements in one call might be worth
investigating. Given the holiday season though, I haven't actually done
much work to see if PQexec actually does support this. I'd be surprised
if a client-server or n-tier app wouldn't benefit from this
functionality.