i'm reading old emails. we have official e164.arpa zones delegated in finland for our landline and also for some mobile network numbers. for example,
harjus:~/tut% host -t naptr 0.5.4.9.2.1.4.6.8.5.3.e164.arpa. 0.5.4.9.2.1.4.6.8.5.3.e164.arpa NAPTR 1 1 "u" "E2U+sip" "!^.*$!sip:+35864129450@tutpro.com!i" .
-- juha