Protein quantification - (Sep/02/2010 )

I am trying to quantify a protein in cell lysate that is not well studied, so there are no good ELISA kits out there yet. I have given up on troubleshooting the one ELISA I was able to find. My PI does not want me using Western blot because it is not definitive enough for protein quantification. Any suggestions on the next best option for protein quantification?

Radioimmunoassay

Lowry method/Bradford method.