availability_calendar.module

    array(array('data' => ' ', 'class' => 'calavailable'),
             array('data' => t('Available'), 'class' => 'keystatus')),
    array(array('data' => ' ', 'class' => 'calnotavailable'),
-             array('data' => t('Fully booked'), 'class' => 'keystatus'))             
+             array('data' => t('Fully booked'), 'class' => 'keystatus')),
+    array(array('data' => ' ', 'class' => 'calavailfullbook'),
+             array('data' => t('Available / Fully booked'), 'class' => 'keystatus')),  
+    array(array('data' => ' ', 'class' => 'calfullbookavail'),
+             array('data' => t('Fully booked / Available'), 'class' => 'keystatus')),           
+    array(array('data' => ' ', 'class' => 'calprobookfullbook'),
+             array('data' => t('Provisionally booked / Fully booked'), 'class' => 'keystatus')), 
+    array(array('data' => ' ', 'class' => 'calfullbookprobook'),
+             array('data' => t('Fully booked / Provisionally booked'), 'class' => 'keystatus')),             
+    array(array('data' => ' ', 'class' => 'calavailprobook'),
+             array('data' => t('Available / Provisionally booked'), 'class' => 'keystatus')),
+    array(array('data' => ' ', 'class' => 'calprobookavail'),
+             array('data' => t('Provisionally booked / Available'), 'class' => 'keystatus'))





availability_calendar.module  
     
  $cells = array(); // our container for cells
  foreach ($week as $key => $val) {
    $weeknumber = $key + 1;
   array_push($cells, array('data' => $notes[$weeknumber], 'class' => 'calnote')); // add the note cell to the cells array
    for ($i=0; $i<7; $i++) {
      // if there's a date, it's part of this month
      if ($week[$key][$i]) {
        $todayclass = '';
        if ( $today == $week[$key][$i] . ',' . $month . ',' . $year) {
          $todayclass = 'caltoday';
        }
        if ($day_status[$week[$key][$i]] == 1) { // booked
          array_push($cells, array('data' => $week[$key][$i], 'class' => "calnotavailable $todayclass"));
        }
        elseif ($day_status[$week[$key][$i]] == 2) { // provisionally booked
          array_push($cells, array('data' => $week[$key][$i], 'class' => "calnotavailableprov $todayclass"));
        }            
+        /* Day Multi-Status (A) */
+        elseif ($day_status[$week[$key][$i]] == 3) { // available-fully booked
+          array_push($cells, array('data' => $week[$key][$i], 'class' => "calavailfullbook $todayclass"));
+        }        
+        elseif ($day_status[$week[$key][$i]] == 4) { // fully booked-available
+          array_push($cells, array('data' => $week[$key][$i], 'class' => "calfullbookavail $todayclass"));
+        }
+        /* Day Multi-Status (B) */
+        elseif ($day_status[$week[$key][$i]] == 5) { // provisionally booked-fully booked
+          array_push($cells, array('data' => $week[$key][$i], 'class' => "calprobookfullbook $todayclass"));
+        }
+        elseif ($day_status[$week[$key][$i]] == 6) { // fully booked-provisionally booked
+          array_push($cells, array('data' => $week[$key][$i], 'class' => "calfullbookprobook $todayclass"));
+        }
+        /* Day Multi-Status (C) */
+        elseif ($day_status[$week[$key][$i]] == 7) { // available-provisionally booked
+          array_push($cells, array('data' => $week[$key][$i], 'class' => "calavailprobook $todayclass"));
+        }
+        elseif ($day_status[$week[$key][$i]] == 8) { // provisionally booked-available
+          array_push($cells, array('data' => $week[$key][$i], 'class' => "calprobookavail $todayclass"));
+        }
+        else { // available
+          array_push($cells, array('data' => $week[$key][$i], 'class' => "calavailable $todayclass"));
+        }
        else { // available
          array_push($cells, array('data' => $week[$key][$i], 'class' => "calavailable $todayclass"));
        }
      }        
 
 
 
 
        
availability_calendar.module
               
/**
 * availability_calendars status options.
 */
function availability_calendars_options() {
  // TODO: make these configurable
  return array(
    0 => t('Available'),
    1 => t('Fully booked'),
-    2 => t('Provisionally booked')
+    2 => t('Provisionally booked'),
+    3 => t('Available / Fully booked'),
+    4 => t('Fully booked / Available'),
+    5 => t('Provisionally booked / Fully booked'),
+    6 => t('Fully booked / Provisionally booked'),
+    7 => t('Available / Provisionally booked'),
+    8 => t('Provisionally booked / Available')
  );
}





availability_calendars.css


table.cal tr td.calnotavailable {
  color: #fff;
  text-align: center;
  background: lightpink;
}
+
+ /* Day Multi-Status (A) */
+ table.cal tr td.calavailfullbook {
+   color: #ccc;
+   text-align: center;
+   background: gray;
+ }
+ 
+ table.cal tr td.calfullbookavail {
+   color: #ccc;
+   text-align: center;
+   background: silver;
+ }
+ 
+ /* Day Multi-Status (B) */
+ table.cal tr td.calprobookfullbook {
+   color: #ccc;
+   text-align: center;
+   background: lime;
+ }
+ 
+ table.cal tr td.calfullbookprobook {
+   color: #ccc;
+   text-align: center;
+   background: olive;
+ }
+ 
+ /* Day Multi-Status (C) */
+ table.cal tr td.calavailprobook {
+   color: #ccc;
+   text-align: center;
+   background: teal;
+ }
+ 
+ table.cal tr td.calprobookavail {
+   color: #ccc;
+   text-align: center;
+   background: aqua;
+ }

td.keystatus {
  padding-left: 2px;
}