Should I accept startup equity based on profitability?

Sounds like you're setting yourself up to get "Hollywood accounted", IMO. If you're going to do that, you'll need to be vigilant about establishing just exactly what "profitability" means - if the company is bringing in $2M/yr revenue on COGS of $1M/yr but the founders each decide to pay themselves $600k/yr, is the operation "unprofitable"?