It's not all that awesome, IMHO, but you can have a go if you like. The boiler shape is wrong, for one thing.
Do you have profile drawings of both locos? I know about this one for the A1:
http://www.elegantsteam.com/a1_centenary.html
This guy has some good stuff in his bucket:
http://s405.photobucket.com/user/dirty_ ... t=3&page=0
V2 drawing:
A3 (pre-war Gresley verson, which is basically an A1):
More info about the two classes here:
http://www.lner.info/locos/V/v2.shtml and here:
http://www.lner.info/locos/A/a1a3a10.shtml
The V2 has a different steam dome and cab shape, as well as the front of the loco being shortened. The running boards are a different height, with no wheel arches. Also the drivers are not at equal spacings on the V2.
To get a good job of a V2 out of the A1 model (and personally I'm not interested in any other sort of job) you'd have to edit classa1l_Body.3dp quite a bit. The cab shape will be problematic because the framework simply doesn't have the vertices you'd need to get an accurate V2 cab. They could be added, if you're keen.
The boiler/firebox does have enough vertices to get the right shape, and looking at it I'm not sure why they didn't use them in the A1 model. They got a bit slack there. Really the A1 should be revamped.
The V2 has a very different steam dome. You could edit the vertices for the existing A1 dome, or add some more if you wanted a better result.
Shortening the front would require moving the cylinders and a fair bit of other stuff towards the rear. That's not that difficult, although a bit tedious.
Moving the wheels to the correct spacing would require editing the driver and bogie files, which is not hard. You'd also need to change the connecting rod and coupling rod files, or they just flail around in mid air (check the Ye Decapod and Mastodon for that) which looks dumb.
Fortunately, these last ones are simple files. If anyone wants to fix the Decapod and Mastodon too, it wouldn't be hard (I don't have any interest in them myself).
Would also need to edit the front truck file. Probably pistons, lights, and a couple of other minor files. Those ones aren't complex.
Should also change the front length point but could probably get away with ignoring that. Could probably also ignore track attachment points. Those could easily be tweaked later if it looks funny in the game.
Then you'd need to do the actual skinning. That's about all. If you're serious about doing it I can catalogue the vertices for you.