Building a new app in python and need some architecture advice.

[Sam Watson]

Hi, I could use a little help with a project i'm going to build.  I
know I want to use python and wxWindows but thats about all I know.
The client will be linux or windows.  The server will be linux.

Basically, its a client/server app with a rich GUI client.

The big catch is I want to be able to run the client/server remotely
across the web in a secure fashion.  I sort of want to stay away from
a web server based solutions because they seem to be attacked the most
and frankly im not dealing with rocket scientists on the other end.
They certainly arent up to the task of keeping a web server locked
down.  Honeslty, i'm not sure I even am.  I'm a big fan of security
through obscurity.

I need something basically plug and play for them as a server.  Im
looking to walk in to their office with a box running linux, turn it
on, plug it into a cat5 cable and never let them touch it.  They will
only access it from the GUI client.  I will be running SSH for my
admin purposes on the box.  I'm comfortable with securing that.

With that in mind, what would you suggest I use as a
remoting/middleware or transport that will be secure across the web
and offers some type of authentication? 

My first instinct is to use pickle and sockets but i figure there
ought to be a better way.

This is the list of candidates ive come up with so far
XML-RPC (Seems like kind of a waste considering the client and server
are both python)
Pyro (Can i secure this?)
Twisted  (Is this overkill?)
Pure sockets (a lot of infrastructure to write but im pretty
experienced with it)

Should I use postgres as a back end or take a chance on some kind of
Object persistence mechanism?  It has to be rock solid.

Lots of questions....  I'm a C++/Windows guys trying to break out of
purgatory :)

Thanks a lot!