Your model continues to boggle my mind.
I try to perform at least one Bitcoin transaction daily. Either by spending some, buying some, transferring some, or most often by receipt of mining earnings.
Suppose that I am responsible for permanently increasing the daily quantity of transactions by one. Today's adjusted number of transactions reported by Blockchain.info is 58,006, and your model projects a market cap of $1.50 * 58,006 * 58,006 = $5,047,044,054.00. My contribution makes the adjusted number of transactions 58,007, and the corresponding market cap is 5,047,218,073.50. The difference between the two market caps is $174,019.50. As the total number of Bitcoins at the time of writing is 12,591,775, my one incremental daily transaction lifts the corresponding price per bitcoin by 0.013 USD.
Right?
Yes. This is what the model implies, and it has reliably held since the opening of MtGox. Your additional daily transaction adds $174,019.50 of value to the market cap, or $0.013 to each bitcoin. It seems too simple, but on the other hand I cannot believe that the goodness of fit is just coincidence; is there something truly at play here that we haven't fully come to understand?
I do agree with your assessment that one should try to find ways to use the system in useful ways (like you are doing). For my part, I will now be looking to hire people in bitcoin space for contract work that I would have normally hired locally--this will increase usage of the network.