I think dave bauman answer is incomplete since he does not take into account the difference between DVI(single link) & DVI(dual link)
it seems according to DP specs that active converters are needed for DVI(dual link) (the kind of link used between TH2GO & gfx cards)
most screens don't need DVI(dual link) to work (even though the gfx card is a DVI(dual link) output, it also does DVI(single link))
only the highest resolutions with high frequency refresh might need DVI(dual link)
With a single DVI link, the largest resolution possible at 60 Hz is 2.75 megapixels (including blanking interval). For practical purposes, this allows a maximum screen resolution at 60 Hz of 1915 x 1436 pixels (standard 4:3 ratio), 1854 x 1483 pixels (5:4 ratio) or 2098 x 1311 (widescreen 8:5 ratio)
http://en.wikipedia.org/wiki/Digital_Visual_Interface
here's a DP to single link DVI adaptor : http://estore.circuitassembly.com/products/Displayport-to-DVI-D-Adapter-Male-to-Female-Single-Link.html
a few of those would likely be included in final products (at least 1 when the gfx cards sports only DP outputs)