Has anyone tried using a Macbook Air?

Yes, this is what I use with Audirvana Plus. Could not be happier with the set-up, see my previous post on this subject.

http://forum.audiogon.com/cgi-bin/fr.pl?ddgtl&1364947210&openmine&zzMgattmch&4&5#Mgattmch

I use my Mac Mini without a monitor, keyboard or mouse; no clutter at all.
I owned a Macbook Air a coupel years ago and used it mainly for interweb surfing. I believe they have changed them, but mine was the most uncomfortable to hold laptop I have used. The edges of that machine were so sharp it wore the skin off my wrist.

I currently use a 2010 MacBook Air as a server with a Western Digital external drive. It replaced a very old Mac Mini, it was a early intel version. The ram was max out at 2 gig's. The Air was my personal computer. The screen is only 11 inches and had become too small for daily use. I upgraded to a larger screen computer, gave the still perfect Mac Mini to my sister and transferred music server duties to the Air. Also the Air has only 2 gigs of ram.

With regard to iTunes music playback, no real listening change. Yet, Screen Sharing and all remote functions improved. Every click is quicker.

Good Luck

Some Mac laptops have a pretty sharp edge. Sandpaper fixes this right up.