High End Portable Wireless/Bluetooth Speaker

I'm seeking suggestions for the best high end portable (single) speaker. This will ideally be a speaker I can move from room to room or even possibly travel with. Let's say budget is <$2,500. I realize you can't beat stereo sound, and so having the option to pair the speaker is a plus in case I wanted to buy a second down the road. However for now this will be a single speaker. I'd prefer to play music via wifi/ethernet when at home but I'd expect bluetooth as an option if needed.  I'm not super sensitive with the size so long as it could be reasonably placed on various surfaces throughout the house.

I've been eyeing the Devialet Phantom I/II as an example. 

Thanks for your guidance!