Short answer is no, it has to fit into the 16×9 frame. When it downscales your video it will add black bars on the top and bottom to maintain the aspect ratio. Under the Frame Controls tab, turn the Resize Filter to Best.
Can you export from FCP7 as ProRes HQ, use Compressor to change the frame rate to a new ProRes 1080i60 file, then bring that new ProRes file into FCP7 and Export as XDCAM?
The only recorder I can think of quickly that can do SD and HD is the Blackmagic H264 Pro recorder but I’m not sure if your camera has HDMI or SDI out.
H.264 codec with an .MP4 wrapper is what you want for a file type that plays both Mac and PC. Craig Seeman in this forum is really the guy to answer that question.
USB thumb drives are cheap nowadays so that would work as a distribution device. If you have it formatted for FAT32, your max file size would be 4GB.