The Shapechanger Sorcerer bloodline can gain the ability to cast a single transmutation spell per day that normally has a duration of one minute per level for one hour per level at a high enough effective level. A Wizard can gain access to that bloodline via Variant Multiclassing from Pathfinder Unchained or via the Eldritch Heritage feat chain. It isn't permanent, but it does let you spend most of an adventuring day in an altered form.
level 20 bloodrager with shapsifter bloodeline get greater polymorph at will.
if yuu have a way to make them last 10/min per level or longer (or find a spell that does). then a ring of continuity (not sure of corect spelling cost 50k) make any personal spell with duration 10 min per level or greater to last 24 hours. or untill a new personal spell is used.
I can find no mention of this shape changer bloodline in the D20pfsrd though?
It's on page 21 of Legacy of the First World.
All the good polymorphs have been carefully culled from the system and been replaced with plazebos *sigh*
There is a 3rd tier hierophant mythic ability which allows you to do it (enduring blessing). The caster can extend qualifying spells to 24 hours duration with it.
polymorph any object, applied in steps as necessary