I use a Bosch UFLED20-8BD AEGIS 850nm, 20° that I picked up for ~$230 before it was discontinued. It works great at that distance, but unfortunately no longer available.
Scene Electronics have illuminators with 15 degree beams available on AliExpress. They have additional models listed on their website, dunno why they are not available through AliExpress. Shipping is not cheap though, but when I ordered from them using "AliExpress Premium Shipping" it ended up being delivered by DHL at significantly cheaper pricer, but somewhat slower, than if you choose "DHL" explicitly.