Krispy,
The one suggestion I have is to stay with all fiberglass blanks. Like the Lami e glass series. I have broke some off the shelf composites over the years like a Kunnan I had that I really liked
. The glass can take a beating and still perform. I only have one custom and I didn't build it but it is a lami blank 6' wire line rod. I believe it was cut down from something like a BT??7S....the 7 foot slow action boat rod blank which is the staple of jigging rods.
You are right about cost. If you buy the lower end priced guides and blanks you can build your own for relatively short money plus time. And on the flip side you can easily spend $250 on quality higher end parts.
Either way, whatever you use if you build it yourself it becomes a thing of satisfaction. Some day I will do the same. Good Luck.