According to that one eyed devil Magnus there are no Wolves on Fenris (what that means I leave to your assumption?) but there are certainly wolves in the space wolf codex.
However GW has left us with a tricky situation. There is one model for a thunderwolf and frankly I think it looks like some sort of demented squirrel and of course GW being GW its not cheap. £25 a model add on the required necessities to convert them and it becomes an expensive proposition to put together what I consider to be a mandatory squad of five . However the positives are clear, they are GW models and there will never be any issues with fielding them in tournaments.
So other options are required people. As I said in a previous blog to start with I went outside the box as it were and went for giant Wulfen proxies.
For the bodies I used Skaven rat ogres and for the heads and tails I used Goblin Wolf Rider bits. The weapons just came from the plethora of spares in the Space Wolf Box Set. The advantages are clear. They were fairly cheap to put together, I am led to believe from Skaven players that Rat Ogres are fairly pointless and they come in the battleforce so they are easily available on ebay. They are GW made and you have a fairly unique model. Disadvantages you can't really get away with putting them on the same size bases as Canis so you are more prone to template weapons. They also just don't look quite right, they don't fit the fluff really.
So that moves us on to the models made by non GW companies. There are a lot out there and if you look here you will find a far bigger selection than I can provide here but I will give some examples of the two I have seen in person.
The Mr. Dandy models seem to be the most popular on the gaming scene. I have seen them at a number of tournaments on the gaming scene. There are 5 different models and all have inbuilt (Space Marine Style) legs. The cost of them is $90 (about £55) + postage and packaging so at about a Tenner a model its hard to grumble. Down sides are clear GW have the right to stop you using them in their stores but I have never seen it happen yet.
And finally I come on to the Mythicast models. The pics on their website aren't great but these are the thunderwolves I use. They are $73 for 5 plus different wolves plus postage and packaging. They also do a Thunderlord and a Iron priest wolf. So why do I love them? For one I think they are slimmer and more lithe than the Mr. Dandy ones. Which is what I imagine a Frenrisian Wolf to be, its not like they will be chowing down every evening in teh icy wilderness of fenris now will they? They have inbuilt (space marine style) legs and some have cybernetic implants which I love. Again the disadvantages are GW may ask you to not use them however I have been playing with mine for the last 4 months at Warhammer World including at a tournament and no GW employee has mentioned them bar asking where I got them from.
So there you have it. 4 options for Thunderwolves although there are certainly more out there. They are a wonderful unit to use and I only hope that if and when GW bother to produce some their selves they do a better job than the Squirrel.