If it is ever designated for real, I-785 would start where the future Greensboro beltway (Painter Boulevard or I-840) crosses I-85 on the east side of town. It would then run counterclockwise around Painter to the current U.S. 29 freeway, then run north up 29 into Virginia. See the map of future Greensboro freeways. 

U.S. 29 through northern Guilford and Rockingham counties is an Interstate-quality freeway right now. No major improvements are planned for this road, and none are needed for it to qualify as an Interstate. As of late 2000, FUTURE I-785 CORRIDOR signs (above) have been posted on 29 north of the Greensboro area. 

The situation is different closer to the city of Greensboro, however. While U.S. 29 within the city of Greensboro proper has been a freeway for many years, it is quite a substandard one, and is not scheduled to be improved in the near future. Hence U.S. 29 south of Painter Boulevard will not be part of any I-785. The part of Painter Boulevard that would carry I-785 is currently on the state's books as an unfunded project. This means the state does not consider building it a high priority, and funding will not arrive until after 2008. (Other parts of Oainter Boulevard, however, are very much under construction now.) 

There is no set date when this corridor will be signed legitimately as 785. The choice of number is questionable, considering how neither North Carolina nor Virginia has a 185, 385 or 585. Some have suggested this road be numbered I-83, to connect with the existing I-83 north of Baltimore, but frankly the last thing the Triad area needs is another 2-digit Interstate. 
  
Sorry to burst everyone's bubble, but that's really all there is to say right now.