Here's one I did (still doing) on an AONE5:
GIB-LHR-SIN-MEL-ADL, SYD-PER-AYQ, ASP-MEL-JFK, PHL-PHX, LAX-JFK, BOS-SJO-JFK, ORC-ANC-ORD, JFK-SCL, ANF-SCL-GRU-GIG-GRU-SCL-EZE-MIA-LHR-GIB.
Not sure of the mileage and it isn't the most efficient I know (I didn't use any of the Asian sectors), but it was enough to put me through BA Gold another year, renew AA Plat, and then renew Gold again for the following year.