Yes, sold out. In fact, I'm pretty sure the 08/09 Bibby's were sold out completely right around the end of January. So you would have to pre-order through Moment ( http://momentskis.com/mstore/index.php?cPath=28 )or wait until your local shop gets them where they'll probably be marked down.
The new site should be launching soon and will have distribution information.
At your size and given the location, I would suggest the 186. The 190 is pretty beefy when compared to the shorter length and for a dedicated pow ski, you'll appreciate the flat camber more. A friend of mine who's the same height/weight as you skied the 186 Bibby all last year here in Colorado (as long as it wasn't boilerplate) and he loved them.
I really think you'll be plenty stoked - as you can see, you rarely find this ski up for sale.
I have ridden Bents for one season and I am pretty much identical height and weight to you. LOVE THEM!!! Durability wise the tip and tail delaminated within the season but they have gotten warrantied. I ski aggressive all mountain and they are awesome
The Night Train is wider and has huge taper at the tip and tail - this makes the ski really easy to spin and pivot on while keeping the mass of the ski underfoot. The Bibby 186 is a softer playful powder ski that pivots very well, but not as easily as the NT.
NT dims = 140-123-135
Bibby 186 = 143-115-134
So you can see that the NT has much less sidecut and will feel less hooky in powder because of it.
either way i dont think you can go wrong with the bibby or the night train...i really want to try out the night train but i have tried bibby's and they are fantastic...the guys at moment know what they are doing and im not just saying that cause i own some.
The NT seems like it would be the best of the options. And once the snow begins to get tracked out, the exaggerated tapered design will help slice through the crud with ease - I've noticed it on the Bibby which doesn't have as nearly as much taper as the NT.
Whichever you go with, just make sure to never leave your sight. ;)