Right now I have one Google Voice number on one Google Voice Account which I use as my home phone number. I would like to port my business phone number over to Google Voice so I can have my business calls sent to my Obi also. Is there a way I can put both phone numbers (home number and business number) on one Google Voice Account or do I need to open a second Google Voice Account for my business number? If so, will Google Voice permit me to have two Google Voice accounts? -- I would run both accounts through my Obi.
You cannot have more than one phone number per Google Voice account.
AFAIK, there is no limit on the number of Google Voice accounts.
If you port a new number into your GV account, the old number can be kept, for a $20 fee and with some restrictions, see http://googlevoiceblog.blogspot.com/2011/06/make-your-secondary-google-voice-number.html#!/2011/06/make-your-secondary-google-voice-number.html .
If you set up your OBi with two GV accounts, you won't be able have a SIP provider, which may be useful for 911 service, inexpensive international calls, or other features not available on GV. It may be worth it to get a second OBi, e.g. so you could answer a business call, while your wife was talking on the home line.
I personally would not port a business number to GV. While GV is quite reliable, there is practically no support; if you did have a problem, you could lose a lot of business before it was corrected. Depending on your outbound usage and other factors, you might consider Anveo, Callcentric, VOIPo, or Phonepower. If you expect your business to grow, you will want multiple concurrent calls on the same number -- all of these provide at least two channels; you can add more when needed, at additional cost.