I have used these blades for unconventional recip saw duties for quite a while now.  I have trimmed limbs as large as 8" off trees and even cut down smaller trees.  The only limit after the length of the blade is the  length of your extension cord and the breadth of your imagination.  You  will want to use a little slower blade speed to keep the blade from  "whipping," but on thicker wood you can speed it up.  You will  find lots of uses for a recip blade this long.  Maybe timber framing?  I  don't know, but someday I'd like to try it.