It's the small things that make my day sometimes.
Somehow in my flurry of Handel 1.0 programming, I've missed the obvious: how to order the results of cart/item searches. [kudos to Kaare for pointing that out] So I thought to myself "just pass the search method \%options down through storage, and into DBIC resultset \%attributes. Sounds easy.
So, in my cart code, I just altered one line:
# my $results = $storage->search($filter); my $results = $storage->search($filter, $opts);