1) Most expensive MN implementation?
2) Most profiatble?
Dash Masternodes cost about 13.7 BTC right now and make about $1.54 per day (at .013700000 price)
Crave Masternodes cost 1.4 BTC right now and make $2.88 per day (at .00280000 price)
BITCREDIT Banknodes cost around 5 BTC right now and make $9.20 per day (at .00002000 price).
Per BTC return, Crave takes it. But BITCREDIT is definitely the most undervalued right now, with the most room for growth. If the price rises to just 5000 satoshis, one banknode will make around $23 per day. This also doesn't take into account the service income.
I feel like we need someone to start a pooled Banknode service soon. The amount to own your own BN is already high for most and it's going to seem completely unreachable if the price keeps rising. $4.60 per day for 1/5th of a BN is pretty good and a lot more people would probably invest if they knew they could get in on just a piece.