A new MSNBC article "Affordable European deals during the winter" has this nugget:
"Check out www.rentvillas.com, where rates drop almost by half in the low season. A villa in the Val di Pesa region of South Florence, which can accommodate up to 6 people, starts at $585 a week — that’s just $97 per person! High season rates are about $1,100 a week. This Tuscan villa is located in a rural area surrounded by vineyards and olive groves. A medieval farmhouse in Val d'Elsa in the province of Siena can accommodate up to six people, and even includes maid service. At $870 a week, compared to $1,690 in the high season, it’s an unbeatable deal. You might have to bring your sweater, but you'll be Italy surrounded by your friends and family in the Tuscan countryside."
I would caution potential renters to inquire about the heating bill however! It can add up quickly here -