Might be worth checking with your club, as a few are doing lipo trials at the moment. There will be a change over at some point, so clubs are experimenting (or at least watching other clubs experimenting!)
I say this because the club I'm about to start running at started a discussion last week, literally the day after I received my four nimh packs in the post!
I'm not upset, as I haven't joined the club yet, so they had no way of alerting me, and it's a big enough turnout of minis to find someone to race against anyway.