Aggregating string fields in straight SQL under Oracle 8, 9, or 10

Question

I have an application that requires the values of a character field to be aggregated over a number of rows and the result returned as a single string in the resulting row. The function needed is like the LIST function in Sybase SQL:
The LIST aggregate function is different from the others in that it doesn't return a single simple value but a string containing a formatted list of multiple values. The simplest form of LIST evaluates the expression for every row in a group, converts those values to strings, and concatenates them together into one long string with a comma (,) separating each value.
Here is an example that eliminates duplicate values, changes the "," separator to ", ", and sorts the results:
SELECT LIST ( DISTINCT state, ', ' ORDER BY state ) AS different_states
FROM employee
WHERE dept_id = 100;
different_states
================
CO, FL, IL, MI, NY, PA, RI, TX, UT, WY
Is there a way to accomplish this in Oracle SQL short of writing a function similar to LIST in PL/SQL?

Answer 1

Thank you all for your responses. The upshot seems to be that once we are on 10g ( 6mo to a year ) there is hope, but for now a PL/SQL function is probably the only answer.
It seems odd that Sybase is the only DBMS that offers such a useful function in such a simple and elegant form.