Check fewmiles' site for fairly recent prices ex-anywhere. You can easily find the link in the archives. Roughly, in first, ex-Canada is about US$1000 cheaper than ex-US. The downside is that you do need to deal with an agent there - you have to ticket 7 days (?) in advance of departure. Nominally you're supposed to be in-country to pick up the tickets then, but your agent does that for you. No agent will want to ticket you on AA - no commission. Mine has used CX in the past and I've been a happy camper, but last time she used QF and it was a really rough go. Others are happy enough with QF rtw processing, so I guess I got a new kid on their rate desk. (Who tickets you is mostly irrevelant. Some rate desks are reputed to be cleverer than others, and some airlines can print tickets with more coupons than others, but otherwise it's probably not a big deal.)

On the OWE fares, direction is pretty much irrevelant. You can't backtrack across one of the oceans but in-continent you can go back and forth pretty much at will, within your segment limit (and a few other nits.) You can't fly through your starting point. It's an enormously flexible system.