Technically it's profitable to harvest with 10,000 XEM because remote harvesting has zero cost so mining a single block with 0.15XEM in fees puts you in the black ;-).

Right now do not expect much income from harvesting. The fees have just been lowered and many blocks are still empty. A stake of 3 million XEM with an importance of 0.03218% harvests around 1 block per day currently. Harvesting will become more profitable in the future when the NEM blockchain sees higher use.