Sparkync, I have rewired ALOT of very old houses and have never gone about it the way that you are. There has always been a better way in the houses that I have done. Of course the "balloon" walls are by far the easiest but I'm not lucky enough to come across them often. Rewiring the main floor receptacles is straight forward enough that I assume you do not need instruction (let me know otherwise). Second floor receptacles, switches, and lights need to be accessed from the attic. In a large majority of cases, a chase already exists from the basement to the attic (usually where the 3 or 4 inch vent pipe is installed). In the rare case where no such chase is available, look for closets or other inconspicuous areas of the house that line up on the 1st and second floor. In these cases, either run the wire exposed in these "hidden" areas so that they can be easily boxed-off by a trim carpenter or make the minimal sheetrock holes necessary for fishing within those walls. I have ALWAYS found SOME way to get romex to the attic. Once in the attic, I haven't had much problem fishing down to the 2nd floor outlets (maybe I have just been lucky in that reguard). I know I would never be able to use your method of utlizing a 10' extension! The bit would have little chance of staying within the wall cavity! Whatever method you chose, you should let the homeowner know just how much additional labor is involved since the sheetrock was installed first! The bill is going to be huge (in comparison) and the owner needs to know he/she is to blame (not you). I'm not suggesting you be harsh, just matter-of-fact.
