I agree with the others - there are just too many variables to come up with an accurate prediction:
* a 10 pound loss will result in more lost inches on a short person than a tall person
* you don't have any control over where you lose weight from - in any particular week it could come predominantly from your calves, or your thighs, or waist, etc.
* creating a 1 inch loss on someone with a 50 inch waist requires a greater volume of fat than someone with a 40 inch waist.
I do have a theory though (totally UNbacked up by any scientific evidence). A sustainable rate of weight loss is generally reckoned at 1% of your body weight per week, so if you extended this you could probably expect to lose 1% of your inches per week also on a long term average. (Even this theory has a number of mathematical holes in it, but as a crude approximation??)