In reply to ian dawson: Not independent trip, but went on a trip with Tangent Expeditions in May/June to the East cost (North of the Watkins Mountains, skiing south to Gunnbjornsfjeld) went with Tangent expeditions.
Even if you're want to do an independent expedition, it's probably worth talking to Tangent, especially if you're planning to use a ski plane. The cheapest Twin Otter in the region is based in Iceland, Tangent try to run several expeditions at the same time, so the astronomical cost of plane hire is shared between all of the expeditions.
Build in lots of spare time, I went on a 3 week trip, but only spent about 8 days travelling on the ice. We waited 3 days for good weather to get the ski plane onto the ice, then spent 3 days trying to free the ski plane when it got stuck in the snow, then had 3 days during the trip waiting out storms.
Let me know if you've anymore questions, there's loads of photos on my website - see my profile for the address.
Simon