Fuman, I have been asking about this for quite awhile. I would love to see a Starfire XII, I think. But it would depend on a number of factors but a twelve string version of this would be really hard to pass up:
Concerns? The width of the nut. 1 3/4" is great. Narrower than that and I have problems. Early XIIs were narrower as I recall. The other is the tailpiece. I put flatwounds on my 12 so that I don't have to change the strings often but when I do, I really don't want to have to deal with the tailpieces like the Guild trapeze (or the Hagstrom or the Rickenbacker "R"). A stop tailpiece with 12 holes that you don't have to do gymnastics to change strings would be great.
In the meantime, there is a 12 string made by the same company that would make the Starfire XII, that is SPG in Korea. It is a Gretsch Electromatic G5422-12. It does have a 1 3/4" nut and a trapeze tailpiece that you load from the top, not the bottom. That may be just what would do the trick for you. A lot of Guild fans also love Gretsch. I am one of them.