Hornby have replaced these venerable with a newly tooled, cheap Mark I I'm their 'railroad' range over the last 18 months or so. Still an impressive production run nonetheless. The only major fudge was that the full brake was the same length as the opens, sleeper etc when in reality they were shorter. The new railroad models are quite nice by all accounts.
There are two 73 rebuilt projects on the go at the moment, the MTU engined one is for GBRf and they'll use some of them for the sleeper contract in Scotland. The multi-engined apporach has been undertaken by RVEL for Notwork Fail errrr... I mean Network Rail! http://paulbigland.zenfolio.com/p119809187
There are some in America called Gen sets. There is a BR class 73 being converted into one too. 57s were indeed converted from 47s, nearly 20 years ago now by a specialist builder (Brush traction)
GE bypassed EMD in the early 80s when it came to US loco sales with a combination of great deals and the then new SD50 being appalling. However it's interesting that there's not one of the pre Dash 8 era GE locos left running on class 1 railroads while EMD locos of similar and earlier vintage are still running in their thousands.
There is also the new emissions regulations which came into force in January. Not many engines out there are now suitable for locomotives. It'll be interesting to see what IE comes up with turning a relatively simple EMD 2 stroke loco into a complex multi engined rebuild that will have to jump through heaps of red tape. The world has changed since the A Class rebuild, does inchicore still even possess the required skills for such a massive project?
Be surprised if it happened myself.
I read elsewhere that Belmond dont want the colour getting out yet, so it's been painted in this interim livery for testing etc and will then go back in for its final livery closer to the launch date.