Sony and Konami have both filed Arc-related trademarks in Japan.
Sony's filing (spotted by Siliconera) protects the name PlayStation Arc, and arrives a week before the PS3 wand will be playable at GDC 2010. Coincidence? Perhaps Sony's codename for the motion-sensing device stuck.
Konami's simultaneous filing for Gradius Arc (also on Siliconera) may be completely unrelated; but it also may not.
GDC 2010 kicks off next week and we'll be there, chomping through the news.