The cheapest published fare for biz class LAX-PEK seems to be on OZ : $3085 plus taxes. Not a bad price considering that it's virtually unrestricted and will give you full *A bennies and miles.
Edited to add: Air China's unrestricted D fare is slightly cheaper at $2948+taxes

These are decent fares but it's perfectly possible that they could be beat by a good consolidator, especially if your dates are fixed.