I’d check out the NAD CI720s. The also have blueos integrated. Eliminates the need to add multi-zone amps to the CI580. I migrated my house from the CI580s to the 720s (except for one zone still powered by a crown amp). Love them.
Yes and yes. I have 10 of them in 2 of the rack mount accessories. The rack mounts can hold 6 as you note but come with a couple of blank panels you can use if you don’t fill them up. Very quiet also. They do have a fan but it is whisper quiet.
You should be aware that there can be a group sync issue (where grouped zones aren’t playing in sync) with these (and all blueos devices) and roon. I see this occasionally.
Of course not an issue if you don’t intend to group zones. The workaround I use if needed is to group them in the blueos app that doesn’t have this issue and then play them in roon (roon only then sees this as one zone).
Bluesound has said they are working to fix but have given no date.
For me, more compact: 10 zones in 2 3u rack units, Would take 3 580s (1u each and 3 980s (2u each) — so 6u vs 9u. And more power: 720s have 60w per channel vs 50w in the 980.
Advantage of the 580/980 combo is less network connections: 3 (one for each 580) vs 10 for my 10 720s. Also bet you can bridge the 980s if you want 100w per channel in a particular zone (but not sure of this). Can’t do this with the 720s.
So matter of preference. I felt the 720s were the best for me as I had limited rack space and liked the higher power.