Dark Reign 2, from the now defunct Pandemic Studios, is available for $5.99 on GOG.com. Running on a "full 3D engine," Dark Reign 2 continues the adventures of the JDA and Sprawlers soldiers and features "intense action, diverse missions and fairly demanding opponent's AI."
For those itching for an even more old school title in the RTS genre, the original game in the series (released in 1997) is already available on the digital download service.
I hope Dark Reign 1 comes along soon too, unless it's already on GoG. :)
You mean this Dark Reign + expansions? (Which is linked in the article blurb too)