Further to John Moulden's comment above, I can confirm the University of Georgia Press has now begun to offer the 1990 Songs of the People edition as a 'print on demand' item. It can be bought via Amazon and Abebooks from a variety of outlets.

In my post as song cataloguer for Kist o Riches / Tobar an Dualchais, we had been asking UoG Press to consider reprinting to help with the cataloguing work and thankfully it seems to have borne fruit.

Now all we need is a reprint of all volumes of Greig-Duncan!