Yeah you need 2.6.23+ kernel which has the latest berry_charge kernel module. E17 is just a window manager ("just" - hah) so I don't see any reason it couldn't run on top of Mint. Once you got all the bits installed into Mint you'd just have to start E17 instead of GNOME (I am not familiar with Ubuntu's take on "startx" but I'm sure it's similar to Fedora). I vaguely remember messing with E.... E14? a very, very (very) long time ago. That's about as close as I come to knowing much about it.

Another thought for E17: grab the latest berry_charge.c source code file from the kernel version control (or an official release tarball) and try hand compiling it, then hand copying it overtop the old one. I bet that might work, it sounds reasonable...