Not standard supermarkets, but...
- H-Mart usually has Holland chilies
- Wilson Farm (Lexington) often has Holland chilies
- Russo's sometimes has Fresno chilies (not a rare thing, you just can't count on it)
Holland chilis also show up at the southeast Asian groceries around the area
I hope this helps.
10 Pleasant St, Lexington, MA 02421
3 Old Concord Rd, Burlington, MA 01803