I don't know where you can pre-order and pay it off in smaller amounts, but I do know that sites like Amazon don't charge you any money until they actually release the console. For example I've had the PS4 pre-ordered since E3 and no money has been taken out of my account and won't be taken out until it ships.
“Anna, my strong, terrifying Anna.” -Cas
"You lack the testicular fortitude to study under me" -Elodin
“slow and drunk is no match for fast and scared shitless.”-Jacob