Just wanted to post this. I have been using these casesfrom SAFE CASE for quite some time now, they come in several different sizes, from slightly bigger than a Thundertusk, all the way up to wheeled with a pull handle..
Top and bottom have eggbox foam, and usually there's two layers of pluck foam too. They ARE incredibly sturdy, the only time I've had a model break in them was when I stupidly forced a lid closed.. Apart from that, The biggest one will quite happily fit an awkward Nagash or Archaon no problems.. the depth being 23cm..
I buy mine from Clas Ohlson here in Norway, I know they've got branches in other countries too, and I'm positive that you could find them from other sellers. Another plus is that they're priced quite nicely too!