Specimen plants will be expensive of course though some suppliers will have them.

Regarding the actual plants, Pyracantha (most except the dwarf variety 'Teton'), Berberis julianae, Crataegus (Hawthorn), Prunus spinosa (Blackthorn). Regarding Crataegus, there are a couple with particularly severe 2-3in thorns such as C. prunifolia that would stop a Rhino.

If there is a fence for support, strong growing roses such as 'Albertine' would be a good choice too. You could even include a Blackberry such as 'Himalayan Giant' that you could get produce from. It's one of the heavist cropping but you will have to wear gloves!

I've bought established plants before, Guest, they're well worth the money when you need instant mature plants.
I bought evergreen shrubs, not thorny like you want but good, that were about 5' x 5', they transplanted easily and well and provided the necessary privacy that was needed quickly.
Got mine at a GC that i use regularly.

You might consider Yucca. Anyone who has walked past one knows how sharp they are, and I use it to keep the neighbors dog out.

Aciphylla anything that touches it will end up bleeding!

Very good idea for keeping unwanteds out Mg.