Not sure what you mean by accomodating both. If you mean the unit is using either one or the other, then the metal case by PDair especially designed for the extended battery is the way to go. I have it, and no matter which battery you use, it will protect is just as well. It won't be held loose if that's you'r worry.
I live in Brazil, and bought it through
Aximcases and with the 15% discount for Aximsite members I effectively ended up not paying for the shipping and handling. It came in a week's time, and I have been extrtemely satisfied with the purchase. Note that if you don't yet have an extended battery, they sell a case+battery combo for US$55. I also got the Boxwave anti-glare (Rio is a sunny place) screen protector, and can confirm it is outstanding in every aspect.
If by any chance you meant holding both at the same time, I could probably fit the 1100 battery in the space left, but note that you'd also need to have the battery cover for it as well.
Albert