The Tarfful figure was a huge letdown for me. The figure had a silly paint job, and the knees should have been articulated like the Sneak Preview Wookiee Warrior.
If anyone wants to make their Tarfful have better articulated knees, it's actually a very simple custom to do. You need to boil and pop his knees off, and replace with the Wookiee knees. Do a bit of repainting - and presto.
I know some of you don't check out the customs section much - so here's the Tarfful that I made that Dimetrodon posted for me there. Maybe this will help someone out who is frustrated with their current Tarfful -

It is a shame that Hasbro makes so many figures like that, that are so close to being a good figure then they give it a stupid feature... why in the world they gave Tarfful those stupid swivel knees is beyone me.
