As far as Steam killing used game sales: All you need to do is create a separate Steam account for each game, with a separate e-mail address created for each account. Sell the game = after receiving the $$, change the password to the Steam acct to something temporary and send it to the new user, who can then change the associated e-mail.
The reason I say separate e-mail is that Steam probably only allows one associated acct for each e-mail address. Even if they allowed multiple, that would be stupid as they now have proof of your selling the acct.
Yes, it works. My current Steam account started this way, with a purchase of BF2142. I'm not interested in re-selling my Steam games, so I just added onto the account as time went on.