My choice would be the Nidecker Megalight 167XL Camrock.
Not sure about the stiffness for 100KG+, but email Nidecker with your details and ask them, they usually respond really quickly. I reckon it will be fine. This board is designed for the Alps and built here in Switzerland!
My curve ball choice would have been a Burton Fish, but I don't think it will work so well at 100KG (web site says up to 91KG).
I use one in the Alps, OK on the piste to get you to the fun bits, then it is unbeatable in the powder and loose snow. And as for those who think it can only be ridden in powder, watch this.
Stephan Maurer – Full part on a Burton Fish – Whitelines Snowboarding