I don't think anybody mentioned this - if they have, please forgive: The Ideale saddles with alloy rails had not just little rods, but massive flat pieces (see for example the A. Faure in VBQ No. 2 or the Herse on the VBQ web site).
Considering the concern about weight in French cyclotouring circles in those days, I am sure they lightened these as much as they could while still being reliable. Even the bikes for the technical trials didn't go much lighter. Most of the lightening for trials saddles appears to have been done in the leather, only a few holes were drilled in the alloy frames (and maybe they were reprofiled a little).
So, barring any revolutionary advances in aluminum alloys, it makes sense that skimpy alloy rods will bend or break, since they have maybe 1/5 of the material of the Idéales...
(Which is why the technical trials consisted of up to 750 km on rough roads, so that no "show" bikes were built, but actually functioning ones.)
Jan Heine, Seattle
P.S.: The VBQ site is at
http://www.mindspring.com/