Do a search in your area for PMBs or Private Mail Box. These are rental boxes that use a suite address. I don't know if that will really solve your problem or not, but some do offer a street address with a suite number, so it appears to be a physical address.

The other option is to look for part time suites, where you don't actually lease a permanent office. It's more like a time-share, where they have 'x' number of offices, including extra services such as copier and receptionists to take messages for you. Each time you might need it, you'd get the next office available - kind of like how some car dealers are stacking 2 to 4 sales people in the same office. Only as you have a client to meet with, or are making phone calls do you use the office. And if 'yours' is busy, you grab the first available.

I don't know if they offer that in Philly, but it's a big enough city to do it. And, it gives you the physical address and office to satisfy every letter of the law.

I've been hearing some company offering offices on talk radio, but they aren't in my area, so didn't pay much attention. It sounded like what I described though, so I'm sure they are out there, whether national or independent.

Good luck with your search.

Dennis