There's the Custom Saber Shop(here) that has all kinds of options for constructing your own lightsaber. They have a forum connected to the store that has a wealth of knowledge to help on the way to making a personalized lightsaber.
If that's not what your looking for, there's Ultrasabers.com that has a variety of sabers, stunts and such. Personally I'm not big on PVC sabers.
I've heard some bad things about Parks since I've joined the RPF, so I'm wary of shopping there.
There are a ton of other options out there also. You can check the Fx-Saber forums to see what else is out there.
I own a company that makes custom sabers called Saber Concepts. I have been making sabers for 1 year and 4 months and have been machining my own parts for just over 7 months. I have a metal lathe and a mill that I machine the parts with. I also have a background in electronics so wiring any soundcard is not a problem. I can give you references if you need them. Here is a link to my forum website, look under the Saber Concepts Work section for some of my latest work. http://saberconcepts.50.forumer.com/index.php Here is my photobucket site, a lot of the sabers are listed in folders on the left of the page. http://s416.photobucket.com/albums/pp242/wadeh13/ Feel free to email me at saberconcepts@yahoo.com with any questions.
Some just asked a similar question last week. It doesn't hurt to look back a page or 2 to see if someone has already asked the same question as you have.
I would definitely recommend the fx-saber forums as I'm a member there as well. There are a long varied list of custom saber builders there from across many sites including most of the ones mentioned above.