I know that places like PetSmart and other pet supply outlets sell heated inserts that you can put in a regular pet bed and cover with a blanket. It looks a lot like a heating pad.
Drs Foster and Smith have this heated bed:
K&H Thermo Snuggly Sleeper | Heated Pet Beds at DrsFosterSmith.com
Some places have cuddle beds that are like a soft fluffy cave they can go into for warmth. I have one for Gracie that she uses when no one can hold her but at night time her favorite place to go when she is cold is under the covers with me. She has been like this since she was a puppy. Yorkies have no undercoat for insulation so they tend to get chilled easily.