Linden Pub. is in California. I am not affiliated in any way with them. At least I have to encourage them for thinking big. Gluing and painting are always a hit, but rather a pain to clean up after. Things that I have had particular success with are things that I can pre-cut all of the pieces and have them put together.
Bird houses are always a big hit.
Not too many pieces, not too many nails, easy to visualize. I had gotten some books on wooden toys that are a help. Again, I just have to pre-cut everything. Have also had some success with Japanese hand saws with the kids. Being able to cut on the pull stroke is much easier for them than on the push.