Will it ever be possible to display images in more than the primary color RGB color bands/channels?

This question is for the IT geeks with knowledge of additive and subtractive color theory and remote sensing. I've worked with multi-band Thematic Mapper 4 and 5 4 and 7 band imagery for over 10 years in ERDAS 7.5 and ERDAS Imagine software. I understand that multi-band imagery is based on filters that only let a limited amount of wavelengths be recorded in each band, same as narrow as nanometers wide in AVIRIS images. Why can't some way be devised to allow more than 3 color channels to be displayed simultaneously by digital filtering and/or combination?