So I managed to find time to watch Mai no Mahou at last. You were right, it's very good - reminded me a bit of a much more cheaply made, less madcap "My Neighbors the Yamadas". There's nothing about it that especially screams P.A.Works to me, but it is further evidence that Yoshihara is a name to keep an eye on.
Same director as Uchouten... The visual style is indeed quite a departure (just watched 2 minutes). It's obviously cheap, but then this is a commercially-sanctioned advertising, effectively. It does have that daytime-TV look, with a bit of Ghibli in the character designs.