Procedural language functions across servers

I know that the FAQ says that the only way to implement a query across databases
is to use dblink, is this the only way available if additional procedural
languages are installed?

For example, assume I have a production server A that does not have PL/Perl
installed, and a hacker's server B (let's assume this is a separate machine)
complete with every possible bell and whistle. If I want to apply Perl (in a
read-only fashion) to extract data from the production tables is the "best" way
to have a PL/Perl function including references to dblink functions?

Similarly, if I have PostGIS or PL/R on the hacker's server, or- heaven forfend-
both, is the best way to get at the production server still to use dblink?

--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]