A couple of years ago I created Net::CIDR::Lookup that does pretty much the same thing. Either it predated the other modules or I was too thick to find them at this time. While as a pure-Perl module it certainly can't compete with Net::Patricia's XS code, a quick look at Net::IPTrie tells me it would likely be a tad faster than the latter and certainly use less memory. Maybe that will do for now, at least for IPv4. The v6 version uses Bit::Vector which is XS itself though I seem to remember it had some serialization hook support.
I just uploaded V0.5 to CPAN that should be some 10-20% faster than the previous version on searches, BTW.