Prepare to be amazed by the huge swath of new props to play with!
I recently downloaded a huge pack of SFM assets from MaxofS2D's website. I eagerly crammed them into the custom folder and started examining all of them. There truly was an entire content pack's worth of props in there... but many of them had issues. Some would make Hammer freeze, some would make Hammer crash instantly. Many of them had textures that would show up in game but not Hammer, and a few of them plain and simply had none at all. A few props didn't have any models, or didn't fit TF2's artstyle.
So I made a library of all the props, placing them alphabetically and saving after each prop and reloading after every crash. Like crossing a minefield by sending an army of clones out ahead of you! Anyway, I've reached the other side (of the minefield, not the other side... you get what I mean) and I think you will find that all of the props in the .vmf are ready to use. I have included the BSP as well so you can hop into GMod to see all the textures properly.
Needless to say, you need to download this for it to work: http://source.maxofs2d.net/sfm/sfmbeta_content.7z
Hopefully everything works. Let me know if it doesn't.