I'm all in favor of adding lots of shortcuts to other modules, like how Path::Class does for File::Temp and so on.

The first idea I get from looking at your modules would be something like making DBIC resultsets out of file trees, like

$fileSet= $path->find(
  name => qr/.../,
  size => '>=4000',
  dir_filter => sub($d) { ... },
);

# Throws an exception unless MIME::Detect is installed
$fileSet= $fileSet->find(mime_type => 'text/plain');

my $iter= $fileSet->iter;  # depth-first, unless parameter "bfs" given
while (&$iter) {
   ...
}

# if the list is known to be small
my @files= $fileSet->all;
[download]

Then your module could adapt those into a SQL query and cache a directory tree, and then use the same path objects to query that database.