Just to further Raul's comments; the latest Console2 snapshot does indeed work with the latest Minefield. To get the latest snapshot you will need CVS installed. (If you're on OSX then you already have it installed).
Go to http://console2.mozdev.org/source.html - copy and paste the second cvs command into the terminal. Once you have downloaded all the files, go to the "console2/src/console2/" folder and zip up all the files in it. Then rename the file extension to .xpi and you should then be able to install it.
If you CBF doing that, I've uploaded the 0.8a1 version here: http://dl.dropbox.com/u/2067588/console2.xpi
(thanks to the dev for continuing working on this great extension :)