This is an incomplete draft of a patch for bug 11075 in Thunar

draft_alpha_sort_bug11075.patch

diff --git a/thunar/thunar-file.c b/thunar/thunar-file.c
index 60fe3e7..db84c78 100644
--- a/thunar/thunar-file.c
+++ b/thunar/thunar-file.c
@@ -67,6 +67,7 @@
 #include <thunar/thunar-util.h>
 #include <thunar/thunar-dialogs.h>
 #include <thunar/thunar-icon-factory.h>
+#include <thunar/thunar-preferences.h>
 
 
 
@@ -884,6 +885,8 @@ thunar_file_info_reload (ThunarFile   *file,
   gboolean     is_secure = FALSE;
   gchar       *casefold;
   gchar       *path;
+  gboolean    alpha_sort = FALSE;
+  ThunarPreferences *preferences;
 
   _thunar_return_if_fail (THUNAR_IS_FILE (file));
   _thunar_return_if_fail (file->info == NULL || G_IS_FILE_INFO (file->info));
@@ -991,15 +994,27 @@ thunar_file_info_reload (ThunarFile   *file,
         file->display_name = thunar_g_file_get_display_name (file->gfile);
     }
 
+  preferences = thunar_preferences_get ();
+  g_object_get (preferences, "misc-alpha-sort", &alpha_sort, NULL);
+  g_object_unref (preferences);
+
   /* create case sensitive collation key */
-  file->collate_key = g_utf8_collate_key_for_filename (file->display_name, -1);
+  if(alpha_sort)
+    file->collate_key = g_utf8_collate_key (file->display_name, -1);
+  else
+    file->collate_key = g_utf8_collate_key_for_filename (file->display_name, -1);
 
   /* lowercase the display name */
   casefold = g_utf8_casefold (file->display_name, -1);
 
   /* if the lowercase name is equal, only peek the already hash key */
   if (casefold != NULL && strcmp (casefold, file->display_name) != 0)
-    file->collate_key_nocase = g_utf8_collate_key_for_filename (casefold, -1);
+    {
+      if(alpha_sort)
+        file->collate_key_nocase = g_utf8_collate_key (casefold, -1);
+      else
+        file->collate_key_nocase = g_utf8_collate_key_for_filename (casefold, -1);
+    }
   else
     file->collate_key_nocase = file->collate_key;