On localhost. I have the following directory structure:
/share/www/trunk/wp-content/plugins/otherfolders
/share/www/portfolio/wp-content/s
The PHP interpreter resolves symlinks before it processes them. You can do this yourself with the readlink function. PHP resolves the links because it's more efficient for *_once functions and code caches like APC, Xcache etc.
What you propably need is another way to find where a particular installation stores it's files. I'd recommend using {$_SERVER['DOCUMENT_ROOT']}/wp-content/wp-load.php assuming /share/www/portfolio is the document root.