It wasn't easy, but I've finally found a combination of configuration and hacks which made the mod_rewrite based SEO URL's on Serendipity work on my GoDaddy account.
Basically a combination of changes to permalinks (adding a trailing slash to certain items) along with a change in one of the php files with respect to rss links seems to have helped out. I would have preferred a totally Serendipity based solution (i.e. a fix to Serendipity) or a GoDaddy solution (i.e. a mod_rewrite setting), but I guess this will do.
I fully expect my next upgrade of Serendipity to undo my changes
Here's my personal notes on the subject. They are not comprehensive, but they are meant to remind me of what I've done:
1) Enable mod_rewrite
2) Change appropriate permalinks to have trailing /
3) Change include/plugin_internal.inc.php
- Changes here are second instance of index.rss to
have trailing slash
- Also do index.rss1 index.rss2 and comments.rss2