As for charging, I see a number of reasons why it won’t happen.
Space: as it is, the driver cavity is pretty cramped already . See here: pic1pic2 .
Getting additional hardware in there would be very, very tricky. Charging port covers take up space too, so it would either grow externally or shrink internally.
AFAIK there is no small off-the-shelf solution for multi-chemistry single cell charging (besides NiMH being a bitch anyway, with another host of issues…) so it would either mean a discrete solution (lots of space) or somewhat crippled (charge Li cells but leave NiMH/Alkalines alone).
I don't know. Barry has sent me some detailed information about the SP10S circuitry but I'm not that sophisticated to tell what's possible and what's not. So, I will try to get in touch with some guys (e.g. Lexel, gchart) that hopefully will do us the favor to take a look at it. Is there anyone else out here who's experienced in driver designs? Please take into account that Barry asked me to not post the driver schematics publicly here, I guess for reasons of confidentiality.
Meanwhile I have received very helpful feedback from Toykeeper, Barry and Kikkoman. As the SP10S driver uses a PIC12F1822 with limited memory it will be difficult but with some changes (e.g. ATtiny85) and a better boost converter we might get to see a new driver with Andúril and AA as well as 14500 support. As soon as I get any updates I will let you know.