All the prepackaged LED strips are is a long piece of flex-circuit with the LEDs and other associated electronics soldered on. They make them in segments roughly a meter long and solder the segments together end to end (Usually poorly) to make longer cables. For your application this is still a lot of soldering, but three joints per meter is much more reasonable than 3 joints per LED. This would also get rid of the hassle of working with separate wires. They don't make strip with 555's, but that is not to say it couldn't be done.
You should be able to find a fab house that could make a flex circuit version with 555's and the LEDs. You would likely design the strip and then stack them side to side to make a square that would get produced. Either the fab house or you would cut the strips apart and solder them end to end to make the cable. You have to think a little bit about how you protect the flex circuit from the elements, but as long as it is nothing too crazy some clear acrylic spray paint can often do the job. There is a good chance that this may be cheaper than the addressable strip version because you are cutting out a lot of expensive microcontrollers and addressable strip isn't real cheap either. This method is also far simpler which is a huge plus.
All this said, nothing here precludes using a lot of addressable strip and a lot of microcontrollers to get the same effect. No matter what you do I would try to design it with a fairly high DC voltage driving the LEDs, as a half-mile of wire will be more than a little significant.