I was asked to add colorful bars indicating the order status in the orders administration page.
So here's how it's done:

in marketpress.php, change line 1728 from
?><a class=&quot;mp_order_status&quot; href=&quot;edit.php?post_type=product&page=marketpress-orders&order_id=<?php echo $post->ID; ?>&quot; title=&quot;<?php echo __('View Order Details', 'mp'); ?>&quot;><?php echo $text ?></a><?php
to
?><a class=&quot;mp_order_status&quot; href=&quot;edit.php?post_type=product&page=marketpress-orders&order_id=<?php echo $post->ID; ?>&quot; title=&quot;<?php echo __('View Order Details', 'mp'); ?>&quot;><?php echo $text ?></a><div class=&quot;bar&quot;><div class= &quot;<?php echo $post->post_status ?>&quot;</div></div><?php

Then you should go and add somehow some css in there.
I use easyblogging for my clients and have built a custom theme for it so that's where I put my css.

Add the following css (it seems like a lot but it's just to make it prettier)

.mp_orders_status .bar{
  width: 100%;
  height: 18px;
  margin-bottom: 18px;
  overflow: hidden;
  background-color: #f7f7f7;
  background-image: -moz-linear-gradient(top, #f5f5f5, #f9f9f9);
  background-image: -ms-linear-gradient(top, #f5f5f5, #f9f9f9);
  background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#f5f5f5), to(#f9f9f9));
  background-image: -webkit-linear-gradient(top, #f5f5f5, #f9f9f9);
  background-image: -o-linear-gradient(top, #f5f5f5, #f9f9f9);
  background-image: linear-gradient(top, #f5f5f5, #f9f9f9);
  background-repeat: repeat-x;
  -webkit-border-radius: 4px;
     -moz-border-radius: 4px;
          border-radius: 4px;
  filter: progid:dximagetransform.microsoft.gradient(startColorstr='#f5f5f5', endColorstr='#f9f9f9', GradientType=0);
  -webkit-box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.1);
     -moz-box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.1);
          box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.1);
}
.mp_orders_status .bar .order_received,
.mp_orders_status .bar .order_paid,
.mp_orders_status .bar .order_shipped{
  width: 20%;
  height: 18px;
  font-size: 12px;
  color: #ffffff;
  text-align: center;
  text-shadow: 0 -1px 0 rgba(0, 0, 0, 0.25);
  background-color: #5eb95e;
  background-image: -moz-linear-gradient(top, #62c462, #57a957);
  background-image: -ms-linear-gradient(top, #62c462, #57a957);
  background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#62c462), to(#57a957));
  background-image: -webkit-linear-gradient(top, #62c462, #57a957);
  background-image: -o-linear-gradient(top, #62c462, #57a957);
  background-image: linear-gradient(top, #62c462, #57a957);
  background-repeat: repeat-x;
  filter: progid:dximagetransform.microsoft.gradient(startColorstr='#62c462', endColorstr='#57a957', GradientType=0);
  -webkit-box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.15);
     -moz-box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.15);
          box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.15);
  -webkit-box-sizing: border-box;
     -moz-box-sizing: border-box;
      -ms-box-sizing: border-box;
          box-sizing: border-box;
  -webkit-transition: width 0.6s ease;
     -moz-transition: width 0.6s ease;
      -ms-transition: width 0.6s ease;
       -o-transition: width 0.6s ease;
          transition: width 0.6s ease;
}
.mp_orders_status .bar .order_paid{
  width: 60%;
  background-color: #faa732;
  background-image: -moz-linear-gradient(top, #fbb450, #f89406);
  background-image: -ms-linear-gradient(top, #fbb450, #f89406);
  background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#fbb450), to(#f89406));
  background-image: -webkit-linear-gradient(top, #fbb450, #f89406);
  background-image: -o-linear-gradient(top, #fbb450, #f89406);
  background-image: linear-gradient(top, #fbb450, #f89406);
  background-repeat: repeat-x;
  filter: progid:dximagetransform.microsoft.gradient(startColorstr='#fbb450', endColorstr='#f89406', GradientType=0);
}
.mp_orders_status .bar .order_shipped{
  width: 80%;
  background-color: #dd514c;
  background-image: -moz-linear-gradient(top, #ee5f5b, #c43c35);
  background-image: -ms-linear-gradient(top, #ee5f5b, #c43c35);
  background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#ee5f5b), to(#c43c35));
  background-image: -webkit-linear-gradient(top, #ee5f5b, #c43c35);
  background-image: -o-linear-gradient(top, #ee5f5b, #c43c35);
  background-image: linear-gradient(top, #ee5f5b, #c43c35);
  background-repeat: repeat-x;
  filter: progid:dximagetransform.microsoft.gradient(startColorstr='#ee5f5b', endColorstr='#c43c35', GradientType=0);
}
.widefat tr.status-order_received td a.mp_order_status{background: none;}
.widefat tr.status-order_paid td a.mp_order_status{background: none;}
.widefat tr.status-order_shipped td a.mp_order_status{background: none;}

You can see the end result in the screenshots below. The first one is the way MarketPress intended it to be, the second one is what it becomes like after we apply our changes.