First, try bleeding when cool using an alternative method. Search me, "bleeding 4K rpms 20 secs.' I hope that one of my posts comes up for you.
Also, you know you can just remove the thermostat from the housing and try that. If coolant is totally fresh, you can reuse it if you're able to catch and strain it (use paint strainer)...but in my experience, it's not worth it.
I think while you're trouble shooting, that you 'should' drain from block, fill SLOWLY with distilled (even slower than that!) while in pos 2, heater on high, fan on low (usual bleeding instructions).
You were bleeding while the car was hot, so you'd expect to see bubbles come up and the coolant rise.
If you didn't replace ET cap, that would be one place you might get lucky.
Also, there are two issues with bubbles that I know of...one, they can block a passage, and two, they can cause the wp to cavitate and not pump coolant at all.
I'll assume all components were OE...if not, AM therm is often a problem.
If you haven't done it yet, check radiator from underneath. Many here put in the wrong radiator or its leveling screw. My replacement Behr didn't have the screw like my original OE rad did, so you need the right Behr. If you have an OE rad with leveling screw, you might have the wrong screw in and thus you'd leak from behind the ET bracket.
Right now, since you've almost replaced everything (only hoses and temp sensor are still original it sounds like), I hope it's just a little thing and doesn't require that you replace everything again. But don't assume anything new is working right...they sometimes don't. Also, when a radiator blows, that pressure build up can also break the ET, which gets a fine crack in the corner that's barely noticeable when shut off because it closes up tight. Look closely.
In NJ--Tierney's in Montclair, Sept. 25, 7:30 p.m.
In NYC Sat, Sept. 30, 8 p.m. at Broadway Comedy Club! Sat, Oct. 8, 6 p.m. at Greenwich Village Comedy Club.
Comedy can be a great cheap date!
Mangofy your E46!