I, too am very interested in this project. There are several freeware options that come close, but don't completely hit the mark in my opinion. I've used FS Economy, various virtual airlines, and Air Hauler2. Realism is key for me. I own several REX products, and have been a customer for many years. I am confident you folks can put together an attractive, realistic product. My advice is to find a way to entice pilots to fly. Give purpose behind flying other than simple reputation. The currency idea is great - but what to do with the money? I only fly 737ng, so realistically - I would never be able to afford my own plane. And why would I want to - other than making more money... Other than purchasing planes, what would encourage me to make more $$ (aka: fly more routes)? Perhaps using cash to invest in airport facilities others own (with some return on investment) , or use it to purchase facilities at airports myself? That has always been a question in my mind. If there was some reason, or purpose behind making virtual dollars, it would keep my interest much longer.
Just my 2 cents.