ecoli,

I too have used the 6061 for the same reasons that you stated, but as I said, I almost invariably wind up wishing that I had used 7075.

I just might find out how easy it is to tweak a 6061 chassis. It would just suck to put all of that work into the chassis and then wreck it because it wasn't strong enough.

As for the powder coating, it is nice; but will chip at the screw holes and actually make tightening the screws more of a chore. The anodizing will be much more abrasion resistant.

I actually have a tool handle that I made out of 6061 and knurled it at the grip portion and had it anodized type III mil spec (green). Although I can knock it against a piece of metal and ding it, because of the relatively weak 6061; I have also used the knurled part to saw through wrought iron without damage to the finish.