I'm not sure if this counts as "scratch built" but I have been making use of Instant Mold and Green Stuff to make all the extra parts for the models in my current diorama. In August I took a trip to Toronto for a work commitment, and my bits box and tools followed me so I could make the helmets, "eagle" torsos and shoulder pads for my Emperor's Children, though I forgot to snap any photos before starting on the undercoating. I realised then that something was missing, and set about re-creating some of the extra details of the armour on the legs of the models.
I raided my bits box for an approximation of the width I would be needing, after two failed attempts with green stuff or strips of card. A spare dreadnought sarcophagus provided the required piece, which I was then able to copy using Instant Mold. I created various depths and planned to stick to one model at a time, but with my self imposed "start of painting" deadline approaching I ended up making many many copies to glue all in one evening and smooth over the following night with some more Green Stuff.
Pretty soon I had a production line rolling, and for only three models it was quite a quick process barring the usual super-glue-and-fingers swearing! I have always wanted to start an Emperor's Children army (who doesn't want to strike at Initiative 5 in combat? Hello 5th Ed. Blood Angels!) but a project like this gives me a fraction of the effort for almost the same visual reward without doing 50 of these guys and losing my patience with little green strips! After allowing the Green Stuff to dry it was time to clean all the residue from the glues, resins, and so on that might be stuck on the surface which would prevent paint from adhering. A quick undercoat with GW spray and I was ready to choose the right shade of purple.
I haven't been taking many painting progress shots as I change the colours and glazes daily, so any photos may not match future work, though I have a quick snap of the most developed part of the diorama to share with you. It's definitely a work in progress but you can see the final armour I have been putting together using green stuff. This model started life as a 4th Ed Space Marine from my bits box and all the additional parts have been copied from various banner tops (for the chest eagle), Power Fists (for the shoulder guard) and some of the work you see above. I have just started on painting the gold and added the loin cloth to reduce the negative space on the model.
For now it's back to the painting table, though I have also been reading Dan Abnett's "Pariah" in anticipation of a new book in the trilogy this year. Sending you some "get things done" vibes from my painting table Dan!