Update: Added a little more consistent example code.

[%# Template File %]
[% META
    # META is a kind of a new tag, and stores perl 
    # code for each key needed by the Template.
    title => sub { use Class::DBI::AutoLoader( %params );
                   return DATA::Table->retrieve(code=>'A');
                 }
    name => sub { return +shift @NAMES || 'Default Name' }
%]
[% title %]
And here goes the template text, and the template [% name %].
[download]

---

# Perl File
# %parameters are your template parameters, don't care.
my $template = new Template( %parameters );
# data will hold template filling data
my %data;
map { $data{$_} = eval $template->code_for( $_ ) } $template->needed_k
+eys( 'Template.tt' );
[download]

In other words, I need an idea for a mechanism that can associate a piece of perl code (in string format) that can be eval()'ed to get the actual value for each variable needed by a template.

Do the Perl Monks have any suggestions of ways of doing this "magic"?

As I need a quick'n'dirty trick, I'll accept any kind of suggestion, provided that there is a minimum change that it works. I just workarrounded it, so now if this is useful in any way, I can try to write a module...