wow, that sounds like a huge job.  how are you fitting that in with your photography business?  Is it just a routine kind of deal, or are you actually restoring the photos too?  What's the out put when done, are you making prints or is this just for digital archiving . . . ?   
What do you charge for that kind of work?  
I usually get two or three restoration jobs a year and I charge $50 per hour (which is too low to make real money and people I have found wont pay much more) for restoration and my normal rates for re prints . . . 
Tony