Your concerns seem simple to deal with...if you would like a BB but don't want to see work email at certain times, configure your device so you don't see it until and unless you want to.
As Ross Perot would say, "It's that simple."
First - email arrival notification via lights and buzzers and noises: I have all email notification turned off on my BB...no lights, sounds, or buzzes of any kind when email arrives. You can control these settings per each email address, so you could still get notification of personal emails, but turn off all notification of work emails arriving.
So that takes care of you worrying due to notification of arrival an incoming work emai.
But wait! When you receive new email on your BB, the Messages (all emails) and Work email icons change to notify you of new email. What about that?!
You simply create a folder on your BB desktop and move the "Messages" icon and work email icons into that folder. When you want to see your work email, go to that folder and look at it - it's all there, no need to wait to go get it, but no need to see it until you want to.
You could also hide or not hide your personal email account icons in subfolders as well, if your email concerns include knowing about personal emails.
Maybe I missed something, but I believe that solves your email concerns...