Hi
Does anyone know if Barajas airport or one of the train stations has luggage lockers that can be rented for a week or so? Or any other ideas on the best way to leave a suitcase in Madrid for a week?

You have luggage lockers both in Barajas and Atocha train station, nevertheless I dont know the possibilites for medium term deposit.

For barajas airport this is the page for the lockers (consigna) spanish only I am afraid.

http://www.aena.es/csee/...

Lockers are available at the airport...follow the consigna signs. I use the one near terminal 2. You pay 2.70€ for the first day or fraction of a day and then 3.38€ for the 2nd to the 15th day. Then they move the stuff to a warehouse for 33.80€ and charge .68€ a day.