brakes have been bled plenty with assistant on the pedal...no air anywhere now and no leaks.
i guess plugging the master cylinder outlets is the next step.
That would be a good thing to do. You can also try to isolate which circuit the problem may be by plugging the individual ports.
I just went through a similar situation with my own car - all new brakes, bled properly, no leaks but no pedal. Ended up having two separate issues; 1) I was using the old drum brake ditribution block which does not have the hold off feature that the disc brake one has and 2) the master cylinder I chose had too large of a bore for the pistons in my front calipers which resulted in inadequate pressure. Couldn't stop the car. Got the correct/appropriate parts and all is right with the world. Just something to consider if you have any non-factory parts.
Before I figured all that out though, I kept bleeding over and over always with the same result. I must have run about 2 gallons of brake fluid through the system thinking there was air in there somewhere but there wasn't any.