I challenge TV Guide.
I do not think Ellen is truly the final cylon. She may very well have been a cylon, but by the same definition so is Starbuck, having died and been resurrected (she actually burned her own body for gods sake.)
I don't think a story line that existed since the miniseries is wrapped up with the easy-to-hate foil Ellen. Plus she's dead so perhaps the 12 cylon models refers to the 12 'active' surviving models.
Part of me expects to see Dualla wake up on a baseship somewhere.
However I am not the foremost BSG scholar on the internet, just a stalwart fan. Feel free to enlighten me.