What about the Handhelds.org Dev Cluster?
http://www.handhelds.org/projects/devcluster.html
I wonder if binaries compiled there would run on a C760 with maslovsky's Cacko ROM 1.21 ?...
Answering myself : yes, it seems they do !
It was a little awkward because the cluster does not work 100% as described on that page (could not get scp to connect). So once I was logged in a guest directory, I got the Elog tarball through wget, uncompressed it and ran make. Then I uploaded the elogd binary to my website, and from there to the Z.
I haven't tested it extensively, but it runs and displays the demo logbook, so I guess it's OK (right gcc/glibc/whatever). Thanks to Tumnus for pointing out this really useful resource !
Stubear sent me the binaries he built on his own Z ; they're not exactly the same size but they work just fine too.
Thanks to all of you, I now have Elog in my pocket... now let's find some interesting uses for it :-)