client_timezone to server_timezone and reverse

HELO

i am looking for strange things:
a timezone conversion AS transparent AS a charset encoding conversion are.

for __example__ (not intending to override the current behavior)

i want to see now()::timestampTZ always the same
(the server side time with the timezone predefined firmly)

and to see now()::timeztamp calculated according to the client_timezone
setting whatever the user set it to.

In addition to the current behavior it whould be NICE to
cast timestamTZ to timestamp taking in account a shift between server
and client time, if client specified his TZ.