>Plasma torch also would work very excellently if you have the grand to buy
>one.

I wish they were that cheap :)  I have one that cuts up to 1" thick. It
makes heat and smoke and the plasma stream is torch-flame like.
I have a choice, and I choose to use a holesaw for making that particular
hole in the van floor.

I notch hundreds of pieces of metal tubing with holesaws.
In my experience, bi-metal hole saws are all pretty much equivalent in
quality and ease of cutting.
Even if you wanted to buy a really good one for lots of money, it wouldn't
work much better than a cheaper one.
I used to buy lenox holesaws at about $10 each.  They don't last any longer
than the $6 no-name bimetal saw.  The lenox are ground and are a little more
accurate and are centered a bit better however.
Like I said before, the teeth tear off before they get dull.  And when it is
that the teeth accidentally tear off, you can never know.

Gary Lee
http://www.telusplanet.net/public/gary2a/vw.htm