It looks like Thunder Force VI will be developed and published by Sega under license from Tecnosoft. I know we all wanted a 3d next gen addition to the series, but it looks like Thunder Force VI will be released on the PS2 sometime in October. I'll take it! I have been waiting for this for almost 10 years.
Directed by Tez Okano the traditional 2D shooter will be rendered 3D, but will keep its 2d horizontal game play. Old levels will be remixed and new levels are inspired from the old ones.
Check out the screen from Videogamerx
You can pre-order at Playasia.com http://www.tecnosoft.com
**There is also a "unofficial" Thunder Force 6.
Back in 1999 Tecnosoft announced that they were working on Thunder Force 6 for the Dreamcast, but got bought by a pachinko company. So the game never got its chance.
2001 introduced a comedy Sega simulation for the Dreamcast called Segagaga. This was done in a funny RPG style. At the end of this game there is a secret shooter unlock called R720. There are two modes to choose from, one being a direct tribute to Thunder Force. It features the Thunder Force 6 ship, Syrinx.
Six years later in 2007 a company called Factory Noise & A.G are producing a game called Broken Thunder. This doujin Thunder Force game features original fonts, phrases, and once again Syrinx. There is a strong chance this might just hit the Dreamcast. SO keep your eyes and ears open.
below is a screen of the opening movie released by Factory Noise
This is Exceliza. Roger. Good Luck