The only ones I found were more the checkbook/wallet, not a "true checkbook" cover. I carry both a wallet and checkbook. Not that I can write very many checks anymore, but when I forget its nearing the 15th of each month, its nice to have my checkbook in the wallet.
But for weekens or trips I just carry the wallet.
Having both is nice, as I put the credit cards and other "store" cards (grocery store, hallmark, etc) in the checkbook that I may use here and there. And my smaller wallet is my every day stuff, DL, ATM card.