I posted my mods in a different TMLE thread, but wanted to contribute to this thread. I've only been able to cook 3 times on it so far due to a hectic schedule, but I couldn't be happier with the BTLE
Exhaust baffle made of sheet metal shaped to the curvature of the main chamber.
Here's a pic with the grates in place. I only lose maybe 2 to 3 inches of cooking surface.
Bent another piece of sheet metal to make a cover for ash pan and attached a handle so I can easily remove if need be
I also made the charcoal basket as everyone has suggested.
Made a tuning plate out of 1/4" steel and sheet metal baffle that rests on top of it. (I ended up removing the baffle as it restricted the airflow too much)
forgot to take pic until there were only scraps left