lol, dave I apologize if I gave you the impression that your entire army needed to be aproved. I was just pickin on you because I always pick on ya.
This forum is for custom stuff that needs to be prior approved. Like, any unit in the allowed books that does not have currently have a model. Or if there is a model it is not realistic that you could purchase it and as such have chosen to make a suitable stand in model. Also, any idea for data sheets of things you would like to see made a reality. I know that there is a lack of data sheets for a number of armies and people would like to see their normal army lists get a bonus for a cool formation they have in mind. Much like the old eldar craft world rules.
So, yea dave you can field anything from the imperial armor books. As long as you have the model actual model, and have it painted and ready to field. Now if you plan on making a hell talon then you would need to post pics and have someone ok the final product.
As for addressing the table restrictions, they tend to be minimal and only one table was not allowing flyers. When the Team forums open for strategic discussions just let your side know what your planning to bring so that there can be an acceptable compromise. I can't see someone telling you tuff nuggets your fly gets junked because we're sticking you on table X. Looks like your on my side this year anyway and I wouldnt tell you that so I think your good.
As for the DD devices. I think maybe you wanna make them a little bigger. Remember these are Dooms Day Devices, they have structure points and cause doom. Make them look intimidating, maybe just a suggestions getting some loose wiring and adding it in to make them look high tech. I know GW's big is a big egyptian style looking coffin, but they don't include a model for frame of reference. Apocalypse units should look epic. ;p
If ya need help bring them down to the store and talk with some of us, I'm sure we can find an easy way to improve upon what I would call a good start to these models.