fretless in a metal band is entirely workable. you would more than likely want to get a coated 'board. or a synthetic material.
I'd recommend very hot pickups as you're going to want to cut through the mix and you're no longer going to have the bite that frets (metal strings vibrating against metal) give you.
I'd also consider hot pickups. maybe in a MM style and possibly adding piezos to the equation.
Jerzy is an amazing builder. I envy you if you're getting one of his basses...!
Yea you read my mind, was considering the piezo MM thing but I'm not very clued in on it's ins and outs.
Its one of those things were everyones been saying "well its really up to you to decide" but I'm so neurotic I cant decide.

Fretless or fretted Jerzy will build a beautiful bass for me.
And dont be too envious Stew my father had to die so I could sell his house to get it!

Maybe I'll get his initials on it somewhere.
This is the band I have to sound match with it anyway.
www.myspace.com/cripplemronioncheck the video.