I personally use the Dakine Fall Line Double, and I can fit two pow skis in there. Infact it's not the length of the 190cm FLD or the height rather it is the width that I have issues with. The bag is only just about wide enough for two set of skis.
The largest bag Dakine make is 200cm the Concourse Double, this is a little wider and deeper too. So I think there is a possibility that you could, if packed well fit two skis and board in it. However, I am by no means saying this will work, try to go to a shop which sells the bag and try and pack it; I actually find shops are ok to comply with this sort of 'prepurchase' practices. I suppose if you're pushed for space, you could always take the bindings of your snowboard, and take these in you hand or main luggage.
There is a third option, which I've just thought of after writing the above, why this whole answer may read in disjointedly. Have you considered a Ski Roll Bag? These thing have no shape, it's just a piece of material which you roll around your skis and then strap it up, so they could stretch in almost any direction. Also they usually are designed to accommodate skis up to ~200cm, so they'll be plenty long. Here's a link to a ski bag roll in the UK -
http://www.skibartlett.com/scott-ski-roll-bag-4-pairs-was-110-15829-p.asp
