Apparently, Shout! Factory is releasing the original Gaiking anime on January 15, 2013 on Amazon for $13.95 and DVD Empire for $15.99. However, this set is an edited version of the original series where the entire TV series gets compiled into three movies, which is a bit disappointing for those who wanted to own the entire series.
Then there is the question if it will be uncut, or if it will be based on the English version that aired on TV during the Force Five weekday block from way back in the days. Since the listed release is still pretty vague, I think that it might be best to hold off until they are more specific about the contents of the DVD set.
With the release of another Go Nagai series, I am still keeping my fingers crossed for someone to bring over the 2005 Gaiking series known as Gaiking: Legend of Daiku-Maryu on DVD one day.