I have read in Ruhlman's book that it is not possible to cure previously frozen pork is that a fact or a Ruhlman rule? I can only source certified pork from a farm 1280km from my house (ZAR).
There's no reason why not. There may be a loss of quality, as with any frozen product, but I doubt it will be noticeable as you're used to eating meat that's been frozen.
I have made sausages from previous frozen pork without a problem. Also bacon works fine. I was under the impression that pork used to be frozen to get rid of Trichinosis? Also, almost all imported meat is transported frozen if the distances are too big