Not really- They used to and youll see them pop up occasionally on ebay (but I wouldnt trust that) cause the only real park hoppers I know of currently are the CM free ones which if they are selling is a pretty bad no-no....
With the one day tickets it is one park or another- You dont have the joy of park hopping-
The only one day park hopper passes I'm aware of and have actually used are the ones for CM's and for those dining at Club 33. Otherwise, none are sold at the ticket both to the general public.
If you know of someone who lives in So. Calif. and are planning on coming before the end of this month; you could have them purchase a So. Calif. Resident Salute special. It's two parks for one but you're only suppose to visit one park a day. You might be able to use both days up on the same day, using it as a one day park hopper. That has been done in the past but I'm not sure if they've tighten up the rules this year.