For those interested in this...
I've finally had the bandwidth to install and work with Oracle 10g Express, mentioned in this thread.
Using the Oracle 9i script provided by Sparx I was able to get up and running without incident. To this point I have done only minimal testing but all appears to work correctly.
My Oracle installation as fresh - there was no Oracle software, client or server - on the machine before the 10g installation. I installed the Unicode version of the Oracle 10g Server package, which installs the Oracle client as well. I immediately tried bringing EA up, with no problems whatsoever, following normal Oracle procedures for a new schema. [Oracle 10g Express does not (seem to) allow customized creation of tablespaces, so I just accepted those offered.]
I have loaded a good sized class hierarchy (the CWM from OMG) into the test model, and accessed it through automation (via .Net). Both worked without incident. It is still too early to tell how the performance stacks up against other EA repository platforms.
Please let me know if any of you try this, and your experiences differ.
David