Boeing is unsurprisingly interested in expanding the utilization of their X-37 program. One concept that has been studied is the X-37C, which is a 165% scaleup of the X-37B designed for cargo and passenger transport to and from the ISS. It would be launched as a payload atop something like the Lockheed Martin Atlas V.
As a passenger transport, it could carry up to seven crewmembers. This would make it an adequate replacement for the Space Shuttle which could, in theory, transport fifty or more (using a payload bay passenger module) but never carried more than 7. As a cargo carrier, it would be of minimal value; the Atlas V launch vehicle could transport a far larger payload sans X-37C.