I registered about 25 of these 1-letter IDN domains back in April and sold 20 of them over the course of the summer at anywhere from $100-$3000 per domain.(Average $1100)
I'm probably saving the rest I have for the future unless I get a nice offer.IDN's are still fairly new so they're tough to appraise,especially non-keyword IDN's like this.
Some people view these 1-letter IDN COM's as novelty junk,others as interesting curiosities worth having in a portfolio "just in case",and still others who see they're serious investment pieces.
All of the approximately 150 one-letter IDN .COM's are long gone.I wouldn't sell it for less than $500 or so.It's at about 50% now,but as browser compatibility around the world goes up,so will the value IMO.
Matt
My best IDN's: Japón.com,Diseño.com,më.com,+ some 1-letter com's.