I canít see that it uses connect_cached; it does expose the database handle via a getter, but thereís no way to set it or to supply your own. Supplying your own would make this and more things possible; that might make a good feature request.
I haven't used DBIx::Simple (and am now looking in to it), but a quick glance at the docs has this constructor:
I would assume this could be used to pass your own DB handle created via connect_cached
++ for a good writeup. I'd definitely be interested on your thoughts on Class::DBI, and a comparision between it and DBIx::Simple.