How does the oil pressure look? Things that can leak are valve covers, intake manifolds, rear main seal. Also, check the oil pressure sending unit. I've seen when those leak a lot of oil when the seal goes bad.
Make sure the crankcase ventilation system isn't clogged. If that is clogged, the internal pressure of the engine will push oil out of every little crack or orifice.
Do you have an oil accumulator setup? If so, check there for leaks. Best thing to do is clean up the engine real good and run it till you see where the leak is coming from.