Such is the case with Jim Foulds and Aaron Sneary's port cullis. I think it's an awesome alternative, and while it may not be the best thing to use, it works really well.
So here is a link to their port cullis they made:
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=623443
I liked what I saw, but it wasn't quite for me. I wanted something a bit more closed off, and smaller. I also wanted a spikey look to the bottom of the port cullis.
So I sent off for a quick $10 Bricklink order and was able to make this:

This thing is STURDY. It does not move, flex, bend, anything. It's also pretty heavy, so it'll go down nicely.
I think it looks FAR better than the port cullis LEGO has been using lately (those big ladder... things) and while I like the look of the Black Monarch's Castle's port cullis, I want to use more Tudor than I can afford to lose by using that port cullis in black.
I also have invisioned placing those technic plates in the floor of my next castle's entrance, so the port cullis will slide down into them when closed, thus further closing off the castle to attackers.
Its also quite handy that the technic plate only allows for 7 tines to do down through it, thus allowing my 9 wide port cullis (to be inserted into an 8 wide door by means of a 10 wide groove where perhaps two SNOT 1xX tiles will keep the port cullis in line) to have two tines that are raised up higher than the rest, easily allowing for string to be strung through them.
So anyway, I just thought I'd share, and give kudos to Jim and Aaron for thinking up the idea, or at least for giving me inspiration.
--Anthony