Suppose I buy a cut of pork belly from a butcher, take it home, and
brine and smoke it to make bacon.  Then, I want to get the hunk of
meat cut into individual bacon strips.  Is there a law that prevents
me from taking my meat back to the butcher and asking him to slice it
for me? (The butcher at one local supermarket believes this to be
true, but did not know exactly what it said or what it was called.) If
this is true, and there's nowhere I can take the bacon to be sliced,
can you recommend a tool that would allow me to slice the bacon
myself?

Try a mandoline.

Here's a link to an example. In my opinion, DO NOT spend the money on
the really expensive ones. I used to work with a world-renowned Chef
who got the $10 plastic ones, and loved them.

http://www.chefscatalog.com/store/catalog/prod.jhtml?itemId=cprod2310128&parentId=search&showCrumb=false

Good luck!

You don't need special tools to slice your meat into bacon if you
freeze the meat first. When you're ready to slice it, simply pull it
out of the freezer and cut it with a good meat knife.

kriswrite

Rival makes an excellent meat slicer that is, in my experience, well
worth the price:

http://www.amazon.com/exec/obidos/ASIN/B00004S9HU/