Placeables are updated a couple times a year; they're big downloads, and downloading them on every client of every player has noticeable expense. It's only a few bucks, so it's not crushing or anything, but it does mean that I don't want to punt out new placeables every time one of them sparkles at a player just so.
The usual process is to drop a link to the models/textures here:
http://www.alandfaraway.info/phpBB3/vie ... 97&t=45522
Most of the links there point to vault posts of finished haks, but that's just because that's how most of our players find stuff. You don't have to do that extra work to get a thing for ALFA. Models and textures are plenty; haks just get models and textures extracted before the rest of the hak is discarded anyway.
... and then when it's time for me to package up the large-filesized haks (creatures, placeables, tilesets) for ALFA's use, the bits we can use all get swept in.