use(d) to

[Arnold Zwicky]

herb stahlke:
 >I've heard "used to" with modals in Indiana.

 >You must/might/may used to have lived in the South.

it's well known that "use(d) to" can combine with some modals, in
"double modal" varieties of southern english: "useta could", for
instance, plus combinations like the ones you cited.  this is
a complication in the pattern, but not a counterexample to
the general conditions of the distributions of modals and "useta".

arnold