I'm waiting to see what if there will be an SDK and what kind of access users will have to the phone. Hopefully it will be wide open.
You started off well but then you went here and jumped on the fail boat.
It will be the Android OS/SDK and already has loads of apps out as Android has been out awhile.
The answers are going to vary wildly based on skill of the users, corporate environment and what they use the computers for. I've seen an insurance company that had 1 SA per 500 machines. They were all running a locked down version of XP, they were almost a kiosk. The users had 1, maybe 2 programs that they used, the insurance system and a mail client. It worked out well. Think blue collar behind a terminal.
On the other hand, an office full of 'empowered' users each with admin rights on their own vista machine, the need for using many various programs and various duties, you may see as low as 50 to 1... Executives constantly on the cutting edge...
It's later than you think, the joint Russian-American space mission has already begun.