I don't totally understand the genetics behind it, but cream is a dilute of red…and I think you have to have the gene present that causes the dilute...and I am thinking it may have been completely bred out of the western population of Basenjis. The only thing that comes close that I have seen a pic of is Siri, but she is more like what we would describe as fawn in other breeds...and is genetically, supposedly not a cream.
Here is a link to her African Stock page :
http://www.basenji.org/african/Siri.htm
I am NO expert in color genetics or history…I am only repeating what I have heard other people say...but, personally, I doubt we will ever see cream, blue, or mahogany tris in Basenjis again, sadly....