I have decided not to bother with the traditional ladder type aiders as they seem cumbersome and easily tangled. I plan to go with Russian Aiders. This too is a new thing which is not new at all. This it the traditional method of aid climbing in the Eastern Block, and it makes a lot more sense to me. Here is a review of a set made by Trango, who unfortunately are not making them any more.
http://www.gearreview.com/russian_aid.asp
Apparently Fish is working on a design and will likely sell Russian Aiders in the near future, but so far they only sell the ring trees.
While looking for the above link I found this article by Dr. Piton, who apparently has become a recent fan of Russian Aiders. (See the last couple of paragraphs in the following link.)
http://www.rockandice.com/drpiton/dr%20piton.132.html
Wile experimenting in my basement I found it was easy to stand (hands free) in my homemade rig with my highest anchor point being at my knee. I was able to ascend a daisy chain easily in this manner. As I understand it this would be like high-stepping in regular aiders (you would have to be in the top step to have the anchor at your knee right?), accept this was quit easy and felt stable.
Teth