Flights to/from Canada may be cheaper in USD than just from USA (yes in prem. cabins).
You might try 2 tix: ORF-Toronto plus Toronto-Japan.
Also try RTW--say UA + CX ORF-ORD-NRT-HKG-LHR-IAD-ORD.
I think u can use CO miles to upg on NW.
Try 1stAirNet (a consolidator that bugs me with email)
JL