Pretty sweet light setup. I really like it. About those shades though... you mention that finding ones you like, that have plenty of airflow are few and fare between, and expensive. But you also mention "modern looking" shades. Have you considered not using a shade at all? I personally think that it would look plenty modern. I wouldn't think that there would be too much light spilling into the room, as concentrated as that beam is.
If there is too much light spilling into the room if you remove the light shades, maybe you could manufacture something out of aluminum flashing? It's what I used on my 10 and 20 watt LED floods, to keep the light from bouncing against the glass, causing algae issues. Bonus is that aluminum flashing is plenty cheap.
As a matter of fact, yes, I always post, or reply, in novels. I'm adding it to my signature because it seems like I say it in every post!
Fraternity of dirt #32 I'm dirty
DIY Asian themed aquarium stand