I travel a lot for extended periods and I picked up the 110 as a way of drawing US dialtone while overseas. The unit is fantastic and is a permanent part of my travel kit. That said I'd like to make a few "pie in the sky" suggestions for future revisions specifically related to travel. I understand that these may be impractical or of limited value to the market you are addressing, but guess it couldn't hurt to ask
1. Implement an interface 'schedule' where you could inhibit the ATA from ringing the FXS. For example it would be nice to program Obi not to ring the phone between 10pm and 7am. I hate getting woken up by calls from back home starting with "Hi is it 3am or 3pm there? I couldn't figure it out..." If the call is unimportant they can leave voice mail, otherwise they can spend a few $ to make a LD call to the hotel if it's urgent. It would be nice if the Obi power light would be perhaps a solid yellow when the inbounds are inhibited. Of course outbound calls should still be able to be made anytime.
2. I don't know if the circuitry requires 12V as provided by the wall transformer or if it's stepped-down to TTL levels with a DC-DC converter but in any case it would be sweet if Obi could run on 5VDC (like the Linksys SPA3102). This way you could use your iPod/Kindle/cell phone USB charger to power the Obi or even a laptop USB port in a pinch. One less wall wart to carry (or accidentally leave behind) is a very good thing.
3. Minor firmware change -- add GMT + 09:30 for South Australia. I noticed that you support GMT + 05:45 for our friends in Kathmandu (pop about 1.4 million). but think the 1.6M around Adelaide might supply more customer prospects for your products.
Anyway hope we can get more ideas here from the Obi community specifically relating to taking it on the road and thanks for making such a superb product!