Rarely does one find something entirely new at a model exhibition, but it does seem that 3D printing is now a practical possibility. It has been much talked up:

http://www.bbc.co.uk/news/technology-16503443

At the London Model Engineerting Exhibition, this firm was offering a complete service. Anything you can model as a prototype, or design on a CAD programme, can now be reproduced in solid form - from parts to whole loco/coach bodies. This offers the intriguing possibility of small runs of models of prototypes that major manufacturers will never look at and it could replace products from manufacturers like Apocopa and Gecomodel, who no longer have an offer in G/IIm..

http://www.impossiblecreations.co.uk/

And given that the technology is dropping in price, it may soon be possible for one or two people to buy this equipment themselves...

Awesome new technology not? There was a manufactor at the RailExpo last november that sold N an H0 scale houses and other things. All made using 3D technology. It was amazing to see complex N and H0 open craftman signalposts that were made, printed, in 1 piece.

I had a very good chat with the blokes on the stall today as well at Alexander Palace.
Very tempting.

Did either of you get a price indication for say modelling IIm coach body for example??

Sorry - I didn't. I was told that larger pieces need the "printer" to run for several hours. It probably also depends whether you supply a CAD file or the company has to produce the file from drawings. My object of desire would be something like a body for a six-coupled non-Corpet which could fit a proprietary chassis like Piko, which would be quite cheap even if the valve gear would be all wrong; but I am not going to actually do anything for a while...

I understand that the pricing model is quite complex, and appears to be based on :

An hourly charge to clean up your 3d model file. If its an stl file and conforms to the printers guidelines then this is avoidable.

An hourly machine charge, somewhere in the range of 25-200 GBP per hour

Various volume related charges depending on what your model is made out of. I have seen numbers like 35p - 1 GBP per cm3

Ian Sharples produced some artwork for an etched coach kit for Gscale Mad a few years ago, and I remember him saying that it was a lot more effort than he expected to get the artwork right. I imagine that the same goes for 3d modelling, which is a speciality in its own right.

At those prices, the prospect of acquiring a printer - said to be available in the US for $1300 - $1800 - begins to look attractive, and like all techology the price will fall.

The US 'Maker' machines use a different process to the commercial machines, and can suffer from poor surface quality. My colleagues, who are frustrated by my stubborn refusal to buy an i-anything, have identified a MakerBot as my must have gadget - and they are probably right

I added the link because I knew I couldn't explain it myself, and even if I did, nobody would have believed me.