How do folks!
I bought an interesting scratch-built model on Ebay a little while back. It had been nicely made from brass and aluminium sheet, but was perhaps lacking in the accuracy department and was also welded solid with no mechanical movement possible. Some things I won't change like the hydraulics that run up the centre rather than on the sides of the stick.
I couldn't live with the cab though, so have made a new one at a smaller size and with a bit more detail. I've got some paint coming in the post in the next few days so I can get it in the proper colours. Still need to make a rear counterweight. I cut the old pistons and cylinders off and have made some new ones which will move correctly.
One thing I really need are some decent tracks. I think my best bet are the plastic linked tracks from the Bruder 1:16 CAT bulldozer toy - I can remove the grousers on my bench sander to give a flat pad.
I was trying out a set of TWH Bucyrus 495 tracks, but they're not right.

DSC08416 by
jimbocrombo, on Flickr"/>