Hi Miller,
browsing your s_loader.c code i realized there's a separate case
called .pd_imac, which seems to be .pd_darwin for Mac/Intel.
I don't think this is necessary (and i find it rather confusing), as
separate build architectures are correctly recognized by the OSX
loader routines. I just made a xsample universal build external which
loaded just ok.
To combine binaries you would use lipo, as in
lipo -create i386/xsample.pd_darwin ppc/xsample.pd_darwin -o ub/
xsample.pd_darwin
greetings,
Thomas