Update for anyone who might be taking their MP2 off the shelf soon and the internal batteries are a little long in the tooth.
Found some suitable replacements for pretty cheap at ThinkRC.com. -
http://www.thinkrc.com/product_reviews_write.php?products_id=2810 - lower capacity but they fit in the case which was the biggest challenge.
The weird news is that even though the batteries charged right up after installing them I couldn't get the pre to function. A few emails back and forth with Jerry and he recommended that I put power to the DC input jack since it is wired outside of the on/off switch circuit. Sure enough it works that way so that means the switch has failed. I'm fairly handy but I'm not sure if I'm up to the task of installing a new switch - it's right next to a double stack circuit card and everything is glued in.
Want to get this up and running again to use with the MBHO subcards. I think it will be a perfect match.
I'll give a further update on the replacement battery performance once I get a chance to get the switch fixed. Maybe I'll start by shooting some contact cleaner in there a couple times and working the switch back and forth to see if it's just really dirty....