diff -ur markdown.orig/markdown.php markdown.new/markdown.php
--- markdown.orig/markdown.php	2007-09-26 14:41:22.000000000 -0400
+++ markdown.new/markdown.php	2007-12-04 22:41:10.000000000 -0500
@@ -34,6 +34,12 @@
 @define( 'MARKDOWN_FN_LINK_CLASS',         "" );
 @define( 'MARKDOWN_FN_BACKLINK_CLASS',     "" );
 
+# Highest level of header to generate
+@define( 'MARKDOWN_HEADER_BASE',           1 );
+
+# By default, footnote references for which no footnote is found will be left alone.
+# If this is turned on, they're removed from the output instead.
+@define( 'MARKDOWN_STRIP_UNRESOLVED_FNS',  false );
 
 #
 # WordPress settings:
@@ -879,12 +884,12 @@
 		return $text;
 	}
 	function _doHeaders_callback_setext($matches) {
-		$level = $matches[2]{0} == '=' ? 1 : 2;
+		$level = $matches[2]{0} == '=' ? MARKDOWN_HEADER_BASE : MARKDOWN_HEADER_BASE+1;
 		$block = "<h$level>".$this->runSpanGamut($matches[1])."</h$level>";
 		return "\n" . $this->hashBlock($block) . "\n\n";
 	}
 	function _doHeaders_callback_atx($matches) {
-		$level = strlen($matches[1]);
+		$level = min(strlen($matches[1]) + MARKDOWN_HEADER_BASE - 1, 6);
 		$block = "<h$level>".$this->runSpanGamut($matches[2])."</h$level>";
 		return "\n" . $this->hashBlock($block) . "\n\n";
 	}
@@ -1987,13 +1991,13 @@
 		return " id=\"$attr\"";
 	}
 	function _doHeaders_callback_setext($matches) {
-		$level = $matches[3]{0} == '=' ? 1 : 2;
+		$level = $matches[3]{0} == '=' ? MARKDOWN_HEADER_BASE : MARKDOWN_HEADER_BASE+1;
 		$attr  = $this->_doHeaders_attr($id =& $matches[2]);
 		$block = "<h$level$attr>".$this->runSpanGamut($matches[1])."</h$level>";
 		return "\n" . $this->hashBlock($block) . "\n\n";
 	}
 	function _doHeaders_callback_atx($matches) {
-		$level = strlen($matches[1]);
+		$level = min(strlen($matches[1]) + MARKDOWN_HEADER_BASE - 1, 6);
 		$attr  = $this->_doHeaders_attr($id =& $matches[3]);
 		$block = "<h$level$attr>".$this->runSpanGamut($matches[2])."</h$level>";
 		return "\n" . $this->hashBlock($block) . "\n\n";
@@ -2481,7 +2485,9 @@
 				"<sup id=\"fnref:$node_id\">".
 				"<a href=\"#fn:$node_id\"$attr>$num</a>".
 				"</sup>";
-		}
+		} elseif(MARKDOWN_STRIP_UNRESOLVED_FNS) {
+			return "";
+		}
 		
 		return "[^".$matches[1]."]";
 	}