Hi Gunnar,
> I have been told that Sanskrit, unlike Latin, has also
> a 4th rule:
>
> 4) On the fourth syllable from the end, if both the
> third and the second are short.
Yes.
http://ca.geocities.com/vixcafe/jalogga/sanskrit.html
> But I think that in practice, when reciting Pali, one
> quite simply stresses the long syllables (which means
> that sometimes the stress is quite even, e. g. in the
> Dhammapada line "appassaadaa dukkhaa kaamaa", with
> eight long syllables in a row).
Well, length and stress are different things. In that sense Pali may
be close to ancient Greek:
http://www.prosoidia.com/grkrec.html
Dmytro