Yeah you can. I started making an example device for you but live.meter~ doesnt work with mira yet and meter~ doesn't have a linear option (only db) so you need to do a bit of maths or something. Too early for that! but below is the api snippet. I'm sure you can piece it together.
If you didn't want to use the api you could have a m4l device in every channel and just read the audio level as it comes in and send it to your master device.
Gavspav beat me by a few seconds, and I had forgotten that live.meter~ doesn't work (but will in a close future of course errr... Cycling people ?). Have a look at my previous post though as you will see what I mean about observing output_meter_level...
So to make it usable in Mira, I've come with this. Don't know if this is theoretically correct, but it seems close to the levels indicated by Live... Maybe some kind of exponential scaling would be more precise, but dealing with the levels as they appear in Live GUI has always been tricky, I've spent a lot of time in Lemur trying to match them precisely and the closer solution implied using an array of values.
I know about the scaling, that was just meant to allow the reading on meter~, as this only accepts signals in the -1. 1. range. Maybe there's another solution. You can read the amplitude value in the float box.