My local market has an industrial peanut butter maker. The machine is "pre-filled" with nuts. it turns it into smooth peanut butter. No added oils, salt or sugar. the peanuts may be a little more expensive than the ones at a big supermarket ( i haven't really compared). No machine to buy. and you can put your container under it and turn it on and go do a bit more shopping. but I don't think you should let the machine out of your sight.
Even better, recently they have put one of their employees to work and they make pints and half pints for you - so you don't have to wait at all. The peanut butter is just waiting for you.
I don't think this is totally uncommon among the "higher end" markets. Whole foods has a peanut butter maker and an almond butter maker. You put the peanuts and almonds in yourself. and you get them out of a bulk food bin. But is is whole foods so I expect the nuts to cost a little extra.
Now that I think about it, I should do some price comparisons.
Oh, and if you look around you should be able to find some pure nut butters in the grocery store. I got some cashew nut butter once. It was expensive - but its made from cashews - and they are expensive.
But back to your question. I have a little personal rocket blender and a small Cuisinart. I use the Cuisinart for seeds and nuts, and veggies. one day I forgot what I was doing and used the rocket blender to grind some cashews. I think it worked just as well. Usually, I use the Cuisinart when grinding cashews for Mox-a-rella and other fake cheeses.
For "vegan ice cream" i take a frozen banana and just put it in the rocket blender.