Once upon a time (at least exAustralia until about a year ago) QF and BA did have a ticket that would look very much like a round the world ticket. I think it was Oz->Europe return with the options to go via NA or SA booking in W or B class.

About double the price of a LONEx and limited to the two airlines (and some of their codeshares) so purchasing additional segments in Europe or NA could get expensive.

A reference to the fare basis and rules were posted at the time.

Fred