I talked to a Canadian handspinner about flax and found that Richters Herbs in Goodwood, Ontario sells fibre flax seeds by mail. The variety is called Evelin.
You might remember I purchased fibre flax seed this past spring and gave away small amounts to people I expected were likely to grow it for the experience and possibly save the seed from year to year. Myself, I didn't have a twenty by twenty foot patch of ground to sow. According to the seller's directions that was the minimum space needed to grow enough flax for a handspinner to work with.
Directions on the Richters website say the minimum area needed is twenty square feet or two square meters. If I remember my elementary school math correctly, that is about a five by five foot patch. This is a considerably smaller and more manageable-sounding proposition.
I have heard back from two of the people who grew seed. One had a lovely large fresh green bundle of stalks that she brought in to show our guild. Her bundle was about a double handful in size. Another used her flax stalks, grown in a pot, as part of a workshop to teach people about flax.