Granted, the server might need to send some values to the display, but it should not matter in the least if the client alters those values
Yes, that's part of what I tried to explain. My apologies if that bit got lost in the ramble. Since it's a client/server architecture, changing object attributes cannot affect the server's copy unless I am dumb enough to add in logic to directly or indirectly propagate those changes in the protocol, which--and you'll have to take my word for this--I'm not. :-)
As you put it, though, how to "send some values to the display" from an OO design standpoint was pretty much my question. To that end, your suggestion of borrowing some wisdom from CPAN is well taken. Thanks!