Are you looking for baked or steamed?
For baked, I believe that Tianlai Mart gets them in from Chinatown. They bring fresh bakery up to Palatine from Chinatown on a daily basis. You might be able to call them a day in advance if you have a special request. It is very close to 53.
Tianlai Mart
1266 E Dundee Rd
Palatine, IL 60074
(847) 991-0083
For steamed, you could inquire if Jockey Wok n Roll
website has them in their dim sum selection (11:30am-2pm)
Jockey Wok n Rolls
1017 N Roselle Rd
Hoffman Estates, IL, 60195
(847) 885-0888
Jockey Express
Mitsuwa Market Place
100 E. Algonquin Rd
Arlington Heights, IL
(847) 357-0888