I just received a private email asking if I’ve figured this mystery white space issue out. Sadly, the answer is “No”.
I ran some tests (using the same thing as the test Sitemap Controller above (and using both the PHP4 and PHP5 constructs) However, I’m not experiencing the issues using CI 1.7.1 (official release). I’ve been using this release since it was issued without trouble.
I also have my own SVN repository with my own “tweeked” version of CI that I start with at this point.
I haven’t downloaded any of Ellis Labs latest builds.
If the “out of the box” version is still doing it, PM me and I’ll let you download my copy. My “tweeks” are just some extra application files (no core changes) and the pieces for a nice one-user CMS (like fckeditor and the filemanager etc).
If anyone did figure this space issue out, let us know! I still have a bunch of sites running on the 1.6.* versions that still have errors on the google sitemaps due to the spaces.