Adam, a client of ours for many years, wanted a custom scheme for his spiders. The Arachnarok's had their own particular look he wanted, but its the giant spiders (not very giant when you think about it) that have a scheme that really stands out. We had to do tan and black markings on them, and I feel they came out quite well.
You'll notice the Arachnarok's do not have some parts or their crew glued on -- this is because of packing concerns. These minis have to travel half way across the planet and they're not going to do that safely if they're and awkward shape.
I haven't seen an army like this and was always wondering when we would. The all-forest goblin list has obvious appeal, all GW needs to do is make a forest goblin infantry set - perhaps with a few "all purpose" bits and pieces so they can be used as weapons crew or otherwise converted to replace other goblins, and that would be that.
I've entertained fantasies of doing my own forest goblins force but that's largely been sated by my involvement with this order. I still like the idea though of making a small skirmish force. How an Arachnarok can be fielded with a skirmish force eludes me, unless its just used as a big beasty for a specific terrain board or scenario.
All that would be needed for a forest goblin-themed board would be a couple of abandoned step pyramids form the before times, some jungle (cause lets face it -- these guys need jungle, not random trees from Nova Scotia), and we'd be set.
Idle thoughts perhaps. Perhaps not.