Thank you all for all the kind words. We really appreciate it.
Koreen, no it is the standard 3/2 system. However, there are some callbacks that can change the assignement of acceptance/production cargo slots (For more info:
http://wiki.ttdpatch.net/tiki-index.php ... es_14B_14C_)
So in a certain way, they are done, but with the magic of newgrf.
Dalestan, Koreen was speaking (as i mentionned above) of adding 1 more input cargo slot, and 1 or 2 output cargo slot on industries.
After discussions, it has been decided that ottd and ttdp should both have the same functionnality and thus the callback solution has been designed.
It would have been trivial (to a certain extend) to add those additionnal slots, but it would have broken compatibility.