As far as I know 162 and 7740 are the only train sets that had much yellow in the locomotives. There are various other locos that could possibly be described as Krokodil-ish, but not in yellow
I'm not sure why you think it should be shorter, to me it looks like a Vossloh G1700BB A G1700 is 15 metre-ish long, while, for example the DB V160 family of locos (which the yellow loco from 7939 looks like without its pantograph) is 16 metres long.
However this isn't to criticise your model, which it nice work.
Jeff Christner, a long time ago (1999?), used Kadees on his small Lego switching layout. Unfortunatly his site is no longer online but a copy of his page from another defunct site can be seen at the Wayback Machine http://web.archive.org/web/20080423110002/http://www.ozbricks.com/jediagh/a_trains/projects/kadeeswitches.htm
One thing to consider is that you don't want he couplings to be able to pivot from side to side like Lego ones do. The Kadees do not have the self centering effect produced by the magnet.
I have a set of wheels like this that I purchased new from Lego Supplimentary (the yellow bit in the back of the catalogue) back in the eighties. I bought two packs and one had the red pins. I should have complained at the time but its probably a bit late now! I assume it was a manufacturing error.
I assume they found the original design wasn't strong enough
This pic shows the difference, I suppose it could make a difference if the 'hanging down' bit got in the way of other elements
I hadn't realised the sealed type had been around since 2006, where has the time gone!?
There are usually some spare of the smaller parts in sets
The provisional Bricklink inventory shows most of your spares as spares (I've not compared in detail)
http://www.bricklink.com/catalogItemInv.asp?S=10219-1
There does seem to be more than I would expect, are some to allow for motorising the set?
A few of the comments have mentioned an 'older' or 'classic' style of building here, but I'm not certain what you mean?
I do think that all the vehicles are very nice, well proportioned and with a good consistancy in detailing.
Oh, and I do like the antenae handrails...
I have to say, the wheel placeholder parts do throw the proportions off a bit, but apart from that its a great model. I realy like the cabside cutout shape, whats the part you've used for the lower curve?
Edit: just worked it out, its the new PoP half arch upside down