If you couldn't find what you wanted, would you grow them from seed?
Or engineer them in a lab so that they glow in the dark??
As for me, I'm willing to go about 50 miles or so to a specialist's nursery, or order on the Internet, but I don't collect wild plants. I'll try growing them from seed if I can't find any locally. But that is not always successful! I tried growing Argyrodermas from seed, both in soil mix, and in wet paper towels. The seeds came all the way from S. Africa, but I grew nothing. My Lithops seedlings, on the other hand, seem OK
I've read fascinating stories about botanists going through real Indiana Jones adventures in the Karoo and Argentina, looking for rare succulents and epiphytes. I'm not willing to go quite that far...but how about you??