Hi Tbites,
I haven't yet been able to successfully save dahlia tubers inside during the winter! They usually end up too damp and developing a mould on them. I am going to try again this year, though, especially with this cream one. I adore it.
You're right, the winters are too cold here for most bulbs and tubers to survive and bloom the next Spring - or at least, that has been my experience living here.
A few years ago, I discovered a great small business in Nova Scotia that sells a wide variety of gorgeous dahlia tubers. I haven't ordered from them yet, but would like to. I would rather support small business than large chain stores. Here is the link:
Sid's Dahlias
Each dahlia can be viewed in more detail by clicking on the thumbnail image. Beautiful flowers! :-)