Where are you willing to buy from and how much are you willing to pay? How particular as to which of the CM4s you get? I think there are 32 variations?

I have heard that sometimes Micro Center has had them in stock in store only. Unfortunately none are near enough for me to verify that.

ebay has listings for some.

I've seen product reviews on CNX software and LinuxGizmos suggesting some might be included as part of another product like a nas or special industrial case.