While I don't think it is worthwhile to do this in memory (unless there is just HUGE amounts of data, and I mean HUGE, and how that's going to be useful in a single HTML page I don't know since it would have to be a hundred pages long before I considered it huge), you should read the manual page for Perl interprocess communication and anything you can find about mod_perl (since you are trying to speed up data access, but server instantiation is going to be the bottleneck if I understand your description correctly. And now we have completely baffled the non-gurus who will be maintaining this thing after you.

I would set this up as a series of plain old .txt files or use Data::Dumper if you want to keep it simple and easily maintained.