I have the Sachtler FSB 6 and EX1 and will buy the Nano (+ Swit battery), Arri MMB-1 mattebox and Olof's mounts.

Is this too much for the FSB 6?

And if I added my 2 Sony wireless receivers?

If I wanted to add a Manhattan 8.9" LCD?

Thanks

EDIT: I will also be getting a 10lb teleprompter; so, what head would be a minimum for EX1, Nano+Swit, 1 wireless receiver & teleprompter?

I have loaded my FSB-6 head with an EX1, Arri Mattebox and Sennheiser wireless many times without feeling like it is in any way overloaded. I have a NanoFlash coming this week so I'll test that along with the rest, but my guess is that the FSB-6 can handle it all very easily.

The FSB8 would be better suited than the FSB6.

Just a quick search gives you the data about maximum payloads:
sachtler: Fluid heads (http://www.sachtler.com/index.php?id=651&exp_pid=539&exp_cid=34&exp_mode=product&exp_flag=tech_facts)
It says the FSB 6 can have 6kg (13,2 lbs). Now you know this, you can weigh your set or do the math by calculating the weight of all elements.

Like mentioned before: the FSB 8 might be a safer choice. Just make sure the tripod can handle the load as well.