choose which source options I want to use it for filefield

Yeah this is an obvious problem with the current version. I hacked together something for FileField Insert, but it's really dirty and it looks like #417122: Allow drupal_alter() on Field and Widget Settings is going to get added to CCK, which will be a prerequisite for any kind of stable version of this module.

Is there any way the source options can be restricted via a custom form theme function in template.php? I am trying to wrap my head around the devel themer tool and can't really figure out what would need to go in my function to restrict some of the options.

Sure, you can manually theme the list by copying the theme_filefield_sources_list() function into your theme's template.php, then renaming it to [mytheme]_filefield_sources_list().

Hmm, this seems to only allow me the customise the actual list:

"Upload | Reference existing | Remote URL"

I don't think it will let me remove the subsequent UI containing the upload box etc (haven't actually tried yet). I basically want a form with only the Remote URL option showing. Crazily I am now trying to do this with just CSS, but then the javascript hides the .filefield-source-remote class with an inline style that I can't override. I'll get there eventually.

#436174: Configuration Options