I'm finishing up a board bow that seems to be turning out nicely; however, I think it is going to come in a little under weight.  It is plenty long, so I could pike it.
There is a good article on piking a bow in the summer 05 bowyers journal, but one thing not mentioned is whether or not to reduce the width.
By piking, the nock area will become wider, so I was wondering if I should narrow the limb some as well.  Of course, that will result in some weight loss.
BTW, this is a pyramid style board bow; 72" long, starts out 2.25 at fades with straight taper to .5 tips.

I wouldn't narrow it until you piked it, and took a look at the tiller.  If the tips are stiff at that point, than narrow.  

Thats just me.  I am fairly new to piking myself, and don't like doing it.

Piking a pyramid could be tricking when it come to draw weight, normally you can gain 3-5 lbs per inch off each tip, if you narrow the tips using the same tapper you may not gain near 3 lbs per.Youll just have to play with it.