> this may be a slightly odd question, but I figured it might best be
> asked here.  I'd like to establish a PPP-like session over a regular
> ethernet IP connection.

Given your description, I'd say the thing to do is to use PPP over a
pseudo-tty, with the pty backed by a program that opens a telnet (or
similar) connection to the remote system.  (I've heard that such
programs exist but have never seen one personally.)

> I tried finding out more about PPPoE (of which the name suggests it
> can do the trick),

Not quite.  PPPoE is PPP over Ethernet; you want PPP over IP, or PPP
over something else (eg telnet) over IP.  Unless your host and the
target host are on the same Ethernet (or fake it with encapsulating
bridges or some such), PPPoE will not help you.

> Now, why would I want that?  In short: I'd like a cheap solution to a
> problem.  Time and complexity are of little importance.

> [VPNish thing]

If you don't control the PPP server, what you propose is approximately
impossible to set up; if you do, you don't need to bother with PPP, you
can just encapsulate and tunnel.  (Depending on the reasons behind the
on-campus requirement, you may need to encrypt to satisfy the security
needs the requirement is there to address.  POTS dialup is
significantly harder to tap than random network connections.)

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