Wow! This must be one of the hottest thread in APC although I only post a one sentence post to show my gratitude towards this thread started by Aaron. I have just realised that it is going to reach 50 pages soon (maybe this post has reached 50 pages).
Since reading this thread years ago, I have used this method a few times. I still have a 15 gallon tank using such method today and it's still doing well except for the large amount of BBA attacking the rocks.
The first time I setup one of such tank, I was using top soil. The second tank, I could not find any top soil, so I used clay. I tore down the first tank and re-setup using the same top soil 1-2 years later. The second tank using clay didn't do very well, so I replaced it with ADA Amazonia soil.
All the while I didn't use any dolomite and potash - I could not find them. I could find crushed corals but my water was not acidic, so I thought I didn't need any.
The outcome was not as impressive as Aaron's tank but I was happy with my experiment. Obviously I enjoyed playing with mud....without manure, of course

I'm glad that I could keep the plants alive using this method even though I killed more 10-20 or more varieties of plants along the way in my experiment (I got most of the plants free of charge anyway from friends). At least I managed to learn what plants work for me using this method - Crypt wendtii, Ludwigia repens and Elianthium tenellum work very well for me (still have them today). Corkscrew vallisneria worked very well too but I got rid of them when they tried to dominate the entire tank.
Once again, I would like to thank Aaron for this wonderful thread that inspired me to experiment with the mud. However. my wife will be cursing at you if she knows about you because...... I messed up the bathroom a few times....hahaha