I'm not sure where you live in IL, but if you can get to the Chicago Reptile House In Tinley Park, they had a bunch of baby RB's at the store the last time I was there (which was around halloween). I think they were BRB, but I'm not sure. I"m not really sure what you're referring too by diamond rainbow boa.

You can always try searching through www.kingsnake.com and seeing what you can find in the classified ads.