Unfortunately, no Oneworld members operate LAS-YVR, or anything close to it. AA codeshares on Westjet metal nonstop, or on Alaska via SEA, but north/south Oneworld service in the western US is basically nonexistent, except for AA services between LAX and SFO, LAX and LAS, etc.

In your case I'd probably look hard at Alaska's program. AS is not a Oneworld member, but they partner with most OW airlines, as well as a number of SkyTeam members, so it gives you more flexibility on earning and redemptions. Upgrades on AS metal are also a possibility, again via SEA.