If I take a longboard in my truck, I do a variation of the day bag method described above. However I leave the tailgate up, put the corner of the board in the front corner of the bed, and have the other end stick out over the center of the tailgate. I keep a Small piece of pool noodle with a wedge cut out to slide over the top of the tailgate for extra padding. Run a strap per the board and hook straight down to my bumper or hitch. works good. I even got rear ended carrying two long boards with this setup in another pickup I had and since the boards stick up high enough they were undamaged.
If you want a full bed rack, but don't want to break the bank, have a look at the ones harbor freight has. I believe they are like 250 or so and meant to carry ladders so they should be pretty strong.
I put a bed cap on my old truck and built a hanging rack system inside the cap that could hold up to 4 boards suspended from the top. This way you still have plenty of room in the bed for other stuff or to sleep in while camping on OBX. You can hand wet wetsuits and other stuff from the rack too. I also had a Thule rack on top for the longboard, travel coffin and/or kayaks. Of course your limitation will be in your bed length. If you have a short bed tacoma this probably won't be an option. My old truck was a Chevy HD with the long 8' bed. This, of course, is only if you want to spend over $1,000 on the setup.
i just throw my longboard in the back- never had a problem... sometimes I use a bungie, sometimes not, but i have a long bed. I was just at Harbor Freight the other day and saw the ladder racks they have- I would agree that they are actually pretty sweet! I have seen alot of guys in Hawaii that have just the back rack like you mentioned- or actually more of just a bar- seems to work well!