Thought some might be looking for a stand or holder for their 3400/3500 tablet. This was better than I could have hoped for! I bought this book stand and it fits the 3400/3500 almost perfectly (HxWxD)! The clamps at the bottom are the correct thickness and width. The rear leg of the stand snaps into place and folds easily and can function as a handle to hold the tablet. It is very stable (rubber feet) and light. (BTW, the top piece for holding papers slides down) I just clipped it on and leave it there (it won't slide out easily without turning the grips down/off).
Amazon.com: IVR59000 Book Stand Copyholder, 12-1/2w x 2d x 11-3/8h, Black/Dark Gray: Office Products