Jin Saotome's two latest creations are action figures based on Half-Life's Gordon Freeman (from the Half-Life series) and the 8-bit Bionic Commando. He built these two using G.I. Joe Sigma Six figures, but the results look almost worthy of retail. Freeman and the Commando even come with their signature crowbar and grappling arm, respectively. They are now up for auction on eBay via the Gaming Today link below (news.filefront.com).
Jin Saotome's website features additional custom action figures from other video games: Solid Snake (from Metal Gear Solid), Ryu (from Ninja Gaiden), and Helghast Soldier (from Killzone 2). They are currently not for sale.
The pictures of the figures are attached below.