So here is the (weird) deal. The first volume of Grimm’s Deutsche Rechtsaltertümer is also available as printing on demand, but from another publisher that on their turn do not seem to have volume 2 in their catalogue. The good news is that this volume 1 and volume 2 are scans of the same printing, but somehow Nabu Press sells it in a larger book than the Michigan University… At least I have the work complete (for about $ 90,-…), but if you ask me, you better look for a complete set of two of the old printing or the 1955 reprint.
1899/2010 Nabu Press, isbn 1143501012