I might could do this.

source: 
LAGS
Entry: 
427
Example: 
I might could do this.
Modal 1: 
might
Modal 2: 
could
Gender: 
Female
Race/Ethnicity: 
White
Age: 
50
Level of Education: 
College (Graduate, B.S. degree)
Home Community, Town, or State: 
TN (LaFollette)
Location Collected: 
TN (LaFollette)
Year: 
1972
Relation to Addressee: 
subject to fieldworker
Medium: 
Spoken
Sentence Structure: 
1.0
Status: 
Naturalistic