Try HPshopping.com and follow Pocket PC to your hx4705, then select related products, scroll down to your specific model hx4700 series . You'll find a Bluetooth headset there.
I am looking for a bluetooth headset compatible with the hx4705, does anyone have a recommendation. Most of the reviews only talk about cellphone compatibility.
ddparker

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic