I'm always busy buying models, modifying and custom building. Here are a few things from recent weeks:
An NZG Fuchs 301 that had broken wheels. I put a crane boom on and fitted tracks.

1:50 NZG Fuchs 301 tracked dragline by
****llection, on Flickr"/>
Two Marklin Fuchs 301 shovels. One kept original, one with tracks.

1:50 Marklin Fuchs 301 wheeled and tracked excavator shovels by
****llection, on Flickr"/>
Two Old Cars Fiat Allis machines. Yes yes, I know the tracks aren't quite right on the FE40, but hey ho, they're metal!

1:50 Old Cars Fiat Allis FL20 traxcavator by
****llection, on Flickr"/>

1:50 Old Cars Fiat Allis FE40 excavator by
****llection, on Flickr"/>
I bought a set of pincers so converted a couple of excavators -

1:50 Hitachi and CAT demolition excavators by
****llection, on Flickr"/>
I love the 1:25 First Gear and Speccast construction models, and they pop up on Ebay occasionally for good prices. Here's a TD24 pipe layer.

1:25 Speccast International pipe layer by
****llection, on Flickr"/>
A Fist Gear International 175 tracked loader. Great model.

1:50 First Gear International 175 Traxcavator by
****llection, on Flickr"/>
These little Oxford Diecast models in 1:76 scale are excellent. JCB MK1

1:76 Oxford Diecast JCB MK1 by
****llection, on Flickr"/>
Finally, this appeared on Ebay. Someone's custom, made from a Joal Komatsu loader. It's well done!

1:50 Custom CAT 992C wheel loader by
****llection, on Flickr"/>

1:50 Custom CAT 992C wheel loader by
****llection, on Flickr"/>