Depending on how many Google Accounts are in Use and the variedness of the Google Apps you're using, you could just have a virtual machine open for each...(as long as you have the RAM and processing power to accommodate each without much strain on your Host...

I know it seems ridiculous...but not more ridiculous than any of the other claims made here.

How about this: DO ONE THING AT A TIME. The Human brain can only do one thing well at a time anyway...

Just a thought...

P.S. - I prefer the multiple sign-in, Google-based, approach btw...