I'm finishing a custom stock, and need to find some boiled linseed oil
Look in an art supplies store.
While boiled linseed oil looks very nice, it takes a long time to dry. More common are the "oil finishes" like TruOil, LinSpeed, and a variety of other trade names that are a blend of boiled linseed oil and Japan dryers that accelerate the drying process (drying time goes from days to hours). Others, like Permalyn, ProOil, and others are polyurethane-modifed oil finishes that may or may not contain any boiled linseed oil, but look "kinda like" boiled linseed oil finishes. Same goes for tung oil or teak oil finishes, they may or may not actually have any tung or teak oil in them, they jsut look like that kind of finish. There are many polyurethane oil finishes that look quite nice on wood and give a good durable finish. Make sure whatever you choose is water resistant and solvent resistant.
This stock has a lot of striping in it. It's not really a curly maple, but more like a tiger stripe. Make sense?
It is commonly known as "fiddleback" maple, so called because it was used for (drumroll, please) making the backs (sound boards) of musical instruments. It has been called tiger maple, fiddleback maple, and sound wood. Figured wood is common in many varieties of hardwood, maple having a lot of different figure characteristics (curly, fiddleback, birds-eye, flame, quilted, crotch, etc). Figuring has many causes: it can be "scar tissue" for the tree (like birdseye), or an adaptation by the tree that increases flexibility (fiddleback, flame, quilting), or strengthens high-load areas (crotch), or is a reaction to stresses of different kinds (burl, wave), etc.
Figured wood sells for a premium, and the degree of visibility of the figure has a lot to do with how the wood is sawn, which is one reason the sawyer was one of the higher paid positions in a sawmill.