I had a great time in Ulises' studio: it's really bright and sunny, on a small side but has pretty much anything you need including an umbrella! And since it is a walk up flat, it keeps you fit and sober (trust me, it's a good thing, given that Spanish food and wine are just great!).
A few words about the host: he is super friendly and does everything to be helpful and make your stay as comfortable as possible. I was leaving Madrid overnight and he has let me to leave my luggage at his place!
Many many thanks Ulises, and should you ever come to Moscow, my offer stands!