The most I've ever spent on one journey was 80000 for a 2-segment CX + BA J.
If we are counting return tickets, it's 100000 for CX J LHR-HKG-(2 weeks)-HKG-DXB-(paid to LHR). If we are counting multiple people, then double that 100K, as we don't have kids yet.
This was before the 2015 devaluation.
I now only redeem for RFS or other shorthauls with low taxes&fees as I'd rather not waste time searching for longhaul availability and I barely qualify for status with my cheap ex-EU longhauls anyway.