I tried the copy /b method to create one large .ts file from my 1 minute HiPix .ts files. In most cases this worked, however with a few of the recordings I either had no display or the secondary channel program would play. I found HTDVtoMPEG2 would work in all cases. It also creates a slightly smaller files because you select which channel to transfer. I am able to perfectly playback my recordings in MCE 2005 using the nvidia decoder.
I setup HTDVtoMPEG2 for Transport Stream output, .ts Extension and Maximum size 99999.