[jpstewart]

Something like a cabled 2.5" 50pin FML to 2.5" 50pin FML would be ideal, which is what it seems to show on the picture from the manual I included in my original post link. Maybe that was supposed to come with the Voyager but is missing in mine? If that's the case, I hopefully would just need that Sun part number (and someplace that carries it).

Ah, yes, there is such a cable:  530-2062, 87mm long listed in the Field Engineer's Handbook (item #19).

EDIT: something like this maybe? But I can't tell if it's 2.5" 50pin or 3.5" 50pin

https://www.ebay.com/itm/171834486052

It says 2.54mm pitch, so that's the 3.5" standard.  Look for 2.0mm pitch.