1 - I'd love too, but I just don't have the time. The old Skirmisher still works (well, mostly) and a new version wouldn't really improve the functionality all that much, but still require a shitload of work to get developed. That's a lot to pay for a rather small payoff (considering the small Nexus community) and I simply can't afford it right now.
Of course, with the possibility of Nexus 2 on the horizon, there's also the problem of developing tools, that'll become obsolete next year (or whenever the game comes out, IF it gets released).
2 - The model is included with the game, but I don't think it ever gets used anywhere. When you extract nexus_00.dat, you can find it in meshes\aliens\feher_hajok\feher_destroyer.msh