Good opportunity to find a nice LBS in your hood... Check the Shop Directory for one close to you.
I have cut many a head tube (mostly the WRONG way), and have done numerous Franken-stalls of headsets... I hope I'm finally starting to get it right (or at least close). It sounds like you're on a serious trajectory here... 29er, rigid fork... my kind of build. If you're including a King headset and, say a Vicious Cycles fork, that's a $400 reason to take it to your LBS.
If you're hell-bent on becoming master of your own mechanical domain, the advice/links provided here are very good. Biggest lesson learned for me (when cutting down a headtube)... A. You can always shorten it, but you can't lengthen it. B. Measure 3 times, cut once. and C. Pipe-cutters ensure a nice straight cut, but will typically flare the tube at the cut, causing major headache getting the crown race to fit over the tube, requiring additional filing/sanding... Better to use a hacksaw with a cutting guide (IMO).
But ALL of these things require some (albeit minimal) investment. Unless you're likely to repeat it 2-3 times over the next 2 years, I say use this opportunity to make friends with your LBS...
What are you building, BTW? Good luck!
Peace,
BB