Yes, many Microchip processors can be used as clients. I think you need to stay at the 24F's and above if you want to run a USB host. So, yes, I could use a 24F as the USB host interface and pass off the data to something like a cheaper 18F and use that as a USB client. I was just looking for a one chip solution. I was thinking the USB client (peripheral) could be implemented in software.
Oh, I see the chips you suggest are only the USB part. Or USB to UART. Hum, didn't realize that existed. And now I'm wondering what exactly does that bring to the table. Hum, if there is a HW level shifting feature that needs to happen. Well. Then, I really can't run two USB ports on one PIC. As I do not believe any have more then one set of USB pins. Therefore none have more then one USB "HW level shifter".