Dreamcast games will never be on the Virtual Console. Each DC game is around 1gig in size.
Resident Evil 2 shipped on two CDs for the PlayStation. A CD can contain between 600 MB to 800 MB of data. Two CD's could contain between 1.2 GBs to 1.6 GBs of data. Capcom was able to compress two CDs into a 64 MB cartridge for the N64, back in the 90's. Compression Technology has advanced since that time. Therefore the Dreamcast is viable console for the Virtual console of the Wii.