One of those companies, Milestone, is well known for their NAOMI arcade games as well as their seemingly never-ending support for the Sega Dreamcast. When early reports claimed Milestone was working on a Wii shooter project, the immediate speculation was that it would be a port of one of their current arcade games brought to the Nintendo console. Naturally, the focus narrowed on Karous.
Karous is Milestone's latest NAOMI shooter recently ported to the Dreamcast. Out of the three games currently developed by Milestone for arcades, Karous is the only one that has not seen a release on the PS2 and Gamecube. The limited release for the Dreamcast sold rather strongly for the company, so it is reasonable to assume that they would indeed be feeling out the potential for a port to another console as they have done in the past. Though nothing is set in stone yet, it does seem that is exactly what Milestone has done.