I imagine a rucksack looking something like this. I would suggest less detail into the straps, and more detail into the actual pack. Since the clonk wears suspenders, that could double as backpack straps (so, no actual straps in the backpack model).

However, I think a backpack as a part of character and game design. It might be interesting to have a clonk wear a backpack if he can carry > 2 items. The idea of a clonk actually showing his backpack is something the devs should discuss together (if it is a good design concept, etc).

The "backpack" is actually the clonk's inventory that is not the first and not the second item. So we don't need an ingame model here. Only perhaps add it to the clonk's mesh if Randrian will re-do the clonk model once. But this has no priority.

What we coould use though is a high-poly rendering of the backpack fitting to be displayed for up to 128x128 pixels (as an icon). We will probably have several sketches before we can agree on a final render concept so the other modellers are invited to post their own backpack sketches. Here is some input:

http://ds.heavengames.com/gameinfo/aranna/items.html (botom of the page, to the right)
http://www.dkimages.com/discover/DKIMAGES/Discover/Home/History/Military-History/Soldiers/Medieval-Soldiers/Medieval-Soldiers-6.html

Uhm