You didn't mention what VoIP service you plan to use for the Obi110. No matter which one
(Voip.ms, CallCentric, Avneo, etc.) you use, they will either assign you or you will choose a phone number (it doesn't have to be in your local area code) and that is what anyone with caller ID will see when you place a call. Note that this is the caller ID number only, not the name. The number and the name are two separate fields, and are handled by the standards of the public phone system slightly differently.
> Is there any way I could get my home phone # to show up on their caller ID?
There are two possible ways to do this. 1) port your existing number to any of the VoIP providers, including Google Voice. GV is the big attraction of the Obi devices, no other ATA devices work with GV, GV has no cost calls to anywhere in the US and Canada, thus a nice cost-saving deal. 2) Use one of the VoIP providers who allow you to control the number (Caller ID) and name (Caller ID Name) that is associated with an outgoing call.
Voip.ms is one such provider, I've never used them but I read about it enough to know they do allow doing this.