When people do the math, and realize what promotional power 15% of NEM (>5000 BTC), plus over 1000 unique stakeholders will bring to future value, I see these stakes at auction going for a mega-shit-ton. Then, this makes the 15% worth even more. Its an amazing idea.
10 BTC easy!!
10 BTC/stake would put Market cap @ 40000BTC which is around 20 million. I doubt the auction price will be so high as this may not give superior returns on launching