diff --git a/middleman-core/lib/middleman-core/sitemap/extensions/ignores.rb b/middleman-core/lib/middleman-core/sitemap/extensions/ignores.rb
index 8001f731..602db133 100644
--- a/middleman-core/lib/middleman-core/sitemap/extensions/ignores.rb
+++ b/middleman-core/lib/middleman-core/sitemap/extensions/ignores.rb
@@ -61,10 +61,6 @@ module Middleman::Sitemap::Extensions
         elsif block_given?
           @ignored_callbacks << block
         end
-
-        if @ignored_callbacks.size > original_callback_size
-          @app.sitemap.rebuild_resource_list!(:added_ignore_rule)
-        end
       end
 
       # Whether a path is ignored
@@ -74,13 +70,6 @@ module Middleman::Sitemap::Extensions
         path_clean = ::Middleman::Util.normalize_path(path)
         @ignored_callbacks.any? { |b| b.call(path_clean) }
       end
-
-      # Update the main sitemap resource list
-      # @return [void]
-      def manipulate_resource_list(resources)
-        # No op
-        resources
-      end
     end
   end
 end
diff --git a/middleman-core/lib/middleman-core/sitemap/extensions/proxies.rb b/middleman-core/lib/middleman-core/sitemap/extensions/proxies.rb
index e1545ca2..b421bcea 100644
--- a/middleman-core/lib/middleman-core/sitemap/extensions/proxies.rb
+++ b/middleman-core/lib/middleman-core/sitemap/extensions/proxies.rb
@@ -48,7 +48,9 @@ module Middleman::Sitemap::Extensions
       
       def get_source_file
         if proxy?
-          store.find_resource_by_path(proxied_to).source_file
+          proxy_resource = store.find_resource_by_path(proxied_to)
+          raise "Path #{path} proxies to unknown file #{proxied_to}" unless proxy_resource
+          proxy_resource.source_file
         end
       end
     end
@@ -94,4 +96,4 @@ module Middleman::Sitemap::Extensions
     end
   end
 
-end
\ No newline at end of file
+end
diff --git a/middleman-core/lib/middleman-core/sitemap/store.rb b/middleman-core/lib/middleman-core/sitemap/store.rb
index a5a7cc66..d64015a4 100644
--- a/middleman-core/lib/middleman-core/sitemap/store.rb
+++ b/middleman-core/lib/middleman-core/sitemap/store.rb
@@ -20,7 +20,7 @@ module Middleman::Sitemap
     def initialize(app)
       @app   = app
       @resources = []
-      
+      @_cached_metadata = {}
       @_lookup_cache = { :path => {}, :destination_path => {} }
       @resource_list_manipulators = []
       
@@ -29,11 +29,6 @@ module Middleman::Sitemap
       
       # Proxies
       register_resource_list_manipulator(:proxies, @app.proxy_manager, false)
-      
-      # Ignores
-      register_resource_list_manipulator(:ignores, @app.ignore_manager, false)
-      
-      rebuild_resource_list!(:after_base_init)
     end
 
     # Register a klass which can manipulate the main site map list
@@ -127,6 +122,8 @@ module Middleman::Sitemap
         else
           @_provides_metadata_for_path << [block, matcher, origin]
         end
+
+        @_cached_metadata = {}
       end
       @_provides_metadata_for_path
     end
@@ -135,9 +132,11 @@ module Middleman::Sitemap
     # @param [String] request_path
     # @return [Hash]
     def metadata_for_path(request_path)
+      return @_cached_metadata[request_path] if @_cached_metadata[request_path]
+
       blank_metadata = { :options => {}, :locals => {}, :page => {}, :blocks => [] }
       
-      provides_metadata_for_path.inject(blank_metadata) do |result, (callback, matcher)|
+      @_cached_metadata[request_path] = provides_metadata_for_path.inject(blank_metadata) do |result, (callback, matcher)|
         case matcher
         when Regexp
           next result unless request_path.match(matcher)