I came home last night and turned my 8100 off and can't find it, is there a way to remote power on so I can call it and find it?

No.

If it's off, you'll just have to search. Good luck.

Thanks, I thought it was available on an earlier BB I had, am I just imagining this?

It's never been a feature.
It's impossible to do.
If there's no power... there's no way to communicate with it remotely to tell it to turn on.

There was an application for if the device was on silent you could make it ring....but nothing can be done if the device is off (unless it's set to auto-on.)

I have been through that with my phone. My solution was to program it to automatically turn on every day about the time I get up. That way I can always call it as I am heading out of the house and find it. Works great.