From your research, you may have noted that canna bulbs are actually rhizomes and not a true bulb. A rhizome is a specialized stem that sends up leaves and flowers. What this means is that bulbs can be stored air-dry and rhizomes need to be stored dry but without it drying out.
If your canna 'bulbs' are still pliable, then you may still have viable 'bulbs' to plant. If the 'bulbs' are hard and brittle, forget it.
Here is a site from U. of Minn. that describes how to store a variety of plant 'bulbs'. http://www.extension.umn.edu/distribution/horticulture/DG1117.html
Hope this helps-