Just check, based on manufacturer website list price and specified output power into 8 ohms, I ended up with the top 4 below:
1)Luxman L-590AXII (not sure if it is their highest price integrated amp on $/W)........$9000/30W = $300/Watt
2)Passlabs INT-25..............................................................................................................$7,250/25W = $290/Watt
3)Denon PM-SX..................................................................................................................$7,000/50W = $140/Watt
4)Yamaha A-S3000............................................................................................................$8,000/100W = $80/Watt
5)Marantz PM-10...............................................................................................................$8,000/200W = $40/Watt
All of the above are pure analog, not video no digital (DAC, ADC, DSP etc..)
Are there more expensive ones, analog only integrated amps based on list price/Watt?
So far I see a huge gap between the top 3 and the rest.
In general class D amps such as Bel Canto's would be at disadvantage because of their much higher output.
Still, as soon as we turn to real separates, preamp/power amp, prices jump in order of magnitudes. Integrated amps are like AVRs on diet
except the high price ones like the ones listed and mentioned by Mikado463 and Truthslayer.., that's just me obviously..