Thanks everyone for taking the time to reply to my questions.
I have already bought a bunch of tlc5940, and I want pwm control, so I am pretty much locked into them for now. After seeing this video I did give a 5 ft long cat5e cable a try. I didn't have any female connectors like the guy in the video, so I had to solder the wires to header pins. Maybe I did a crap job on the soldering, but it didn't work. One thing that occurred to me is he is only connecting two tlc5940s. I am trying to connect a 4th one with a long cable. Maybe that is a significant difference?
I have read in other places that reducing clock speed can increase range. But can I do this for the TLCs? That will not interfere with how they communicate/operate? What are the drawbacks?
It seems like RS-485 would solve my problem. But what I am confused by is do I need an arduino at each node? Of course it would not need to be a full arduino, just basically a processor that can talk to the RS485 chip and then send the correct spi signals to the TLC? That sounds like it might be a whole project in of itself. I did some searching for a ready made spi --> RS485 ---> spi device but did not turn anything up. Does anyone know of the existence of a product like that?
I am basically trying to weigh the effort/cost of investigating a node based solution against the pain of just making a bunch of connectors and using a ton of wiring. Going at it from the other direction, is there an efficient way to churn out wires with connectors? 4 segments each needing to connect to each other. The last segment 1 connector, the one before 3 connectors, then 5, then 7 for the first one in the chain and its connecting 7 for a total of 23 connectors. With 18 wires in each connector that is 414 individual connections I have to make! Its amazing how quickly something like this scales up. 10ft of lights didn't really seem like it would be that big of a deal...until I actually tried to do it 
BTW: I really dig that controller for the cricket board.