Sad to say, I think Bachmann have missed this one. The conversion between Mainline & Lima turns out a pretty good model. Add to that, High Level do a nice little chassis for the 94xx. Either way, they'll be somewhat less than the £120-odd that we can realistically expect to see when the model sees the light of day.
I did a conversion model some years back. It 'wasn't bad' but since then, other posters on here have made much better examples of it. I've got a couple to do, when I can find a 'Roundtoit' It's not to say that Bachmann (or others) shouldn't make it. It's just that prevarication doesn't always help.
One locomotive, or ten wagons? Hmmmm.
Cheers,
Ian.