you could... find a nice mature San Pedro cactus- Trichocereus Pachanoi- and extract your desired product from it directly. Unlike peyote this plant grows fairly quickly and has reasonable yields. A guru on a mountain has used a crude aqueous extraction via boiling the sliced cactus flesh in a large excess of water for several (4-6) hours over a fire in a stainless pot. makes for quite a ritual, similar to the way natives of north america have prepared it for ages. A piece of cactus 400-600mm in length and average width for this species (about 75mm) is sufficient for a pretty hefty trip- there are some related alkaloids also extracted this way, but most of it is mescaline. After boiling the liquid soup is decanted and boiled down to a concentrate, which is swallowed. I can personally attest to the extreme bitterness of this concoction- it is indeed quite possibly worse than the worst thing you can imagine. It can also make you instinctively retch, which makes for quite a mental challenge. But the guru did it again many times when he was young, the taste being considered some amusing biological deterernt for weaker souls. he he.
A much improved technique exploits the high concentration of the alkaloids near the surface of the cactus' skin.
1. Take a good, sharp knife, and with the piece of cactus held standing upright on a solid board, run the point from top to bottom along the 6 or so "valleys" that run along the cactus, cutting in about 25-30mm from the skin, and at such an such that the cut is parallel to the other side of the ridge behind which you are cutting. Then doing the same on the other side of the ridge (the next "valley" over) but with the angle the other way, so you cut a diamond-sectioned slice from the length of the cactus.
Work round the whole cactus and cut all the ridges off this way. You can do a separate extraction with the centre, white-fleshed piece, but the concentration is quite low and the volume of material large.
Depending on how much you like your blender, you can also cut the spines off. There was an (AFAIK) incorrect myth that these spines contain strychnine- other species may have this property, but not T. Pachanoi (this species is fairly popular and grows in most warmer climates).
Cut up the diamond-section slices into shorter peices and blend them up to a green puree. Adding a small amount of water to take some stress of the blender is a good idea, as is adding small amounts- this is fairly solid stuff.
Once it's all fine and mushy you can extract the alkaloid with ethanol or warm water, using some muslin or other fine cloth to crudely strain the material, using about 2 or 3 washes of H2O. Then re-filter the collected washings with usual filtering technique. It isn't that practical to filter it all in one run.
Then the volume of solvent can be reduced. Ethanol will probably wash some wax from the skin so you may need to defat before proceeeding with an A/B, using a small amount of toluene, hexane, xylene or similar. The mescaline is in a sulfate form so I'd use water.
You can simply evaporate most of the water at this point and drink this- it is considerably less vile than that produced by extended boiling.
But far more tasteful...
After the A/B (aq. NaOH, pH 10-11, ether or the above solvents), mescaline sulfate crystallizes fairly easily so this is probably the ideal salt to aim for.
Mescaline is way cool but treat it with respect. Too much of this can be *real* hard on you.