The only reason to start out in ski boots is if you are also an avid skier and want to switch back and forth during the day.
Deeluxe Track 700 - stiff but not too stiff.
Bomber TD3 (will work with ski boots if you go that way)
A Coiler, Donek, or Prior metal board about 180-185 and at least 19.5cm wide.
Please note that a very fast board and an ice board are two different things. For serious ice you want something shorter with a shorter sidecut radius so that you can get turns around without building up too much speed. A fast board will be longer and have a radius north of 13m.
Eventually you'll need both, but it sounds like you'll be able to start with the fast board, *IF* you can already *CARVE* your softboot gear. Can you do the Norm? And carve the downhill edge?
If the answer to those questions are no, or "well, kinda" then you should start on something medium like a 175.