We ran a little 24' day racer for years with the RF jib's sheet as a single line, with the midpoint fed through the cringle and the two ends pulled through (whatever that's called!
).. worked great. That sort of setup tends to work best where the sheet is rarely removed/never from the sail.
This gets heavily loaded, of course, so the disadv. is its difficulty to remove in a hurry if that becomes necessary.