Re: using alternative fonts without changing texinfo.tex

[karl]

    but that seems to have no effect on the title font used -- it still
    appears in Computer Modern Roman.

@tex ... @end tex is a TeX group, so all the changes are undone at the
end of it.  You have to do something like this:

@tex
{\globaldefs = 1
\font\...
...
}
@end tex

to make the changes persist.

Hope it flies ...  (You might want to get the latest texinfo.tex, too,
just in case ... ftp://ftp.gnu.org/gun/texinfo.tex)