Thanks. I rarely use "Vars" any more in favor of param(), but I agree it sounds like it could be a good fit here, in combination with a hash comparison function.
I'm recalling that the other piece of wanting this is that the query strings will stored in a database column, and I want them in a canonical form for that, so that two identical queries in a different order will be represented the same.
For that, it sounds like I really do need a "sorted_query_string()" method, which I could supply as a plugin or new method to CGI.pm
Thanks to everyone for the feedback!