I use this snippet to show several fields in my admin backend as readonly, but as noticed in the comments, it does not work on stackedinline/tabularinline. Is there any other wa
If you are running Django 1.3 or later; there's an attribute named ModelAdmin.readonly_fields which you could use.
InlineModelAdmin inherits from ModelAdmin, so you should be able to use it from your inline subclass.
InlineModelAdmin
ModelAdmin