Many of the folks in academics are CP only, but they all then to have a fellowship in the division they run (ie. blood bank, microbiology etc..) Some large private practices may hire a CP only doc to run all the CP parts of the hospital, but normally that is just split up among the AP/CP folks. Many of the pathologists that work for the Red Cross and NIH are likely CP only, but again probably have fellowships. A fellowship in Hematopathology would easily get you a job with CP only.
Any specific interest in CP or are you just thinking of general CP with no fellowship. If the later is the case you could have significant difficulty finding work.