Might have used to.

source: 
LAGS
Entry: 
548
Example: 
Might have used to.
Modal 1: 
might have
Modal 2: 
used to
Gender: 
Male
Race/Ethnicity: 
White
Age: 
50
Level of Education: 
College (2 years)
Home Community, Town, or State: 
GA (Atlanta)
Location Collected: 
GA (Atlanta)
Year: 
1976
Relation to Addressee: 
subject to fieldworker
Medium: 
Spoken
Sentence Structure: 
1.0
Status: 
Naturalistic