I have a USB Bluetooth dongle being shipped from China that might work, as I too have been trying to find a replacement too.
After searching the entire Web I finally found one that has the push button pairing button on it. I should get it it soon and I will post the results. It was very difficult to find one that had the push button on the dongle which is the key which is how it's paired, as long as it supports keyboard hid, it should work.
This it: http://www.buyincoins.com/item/13614.html
I didn't buy it from the above site but found another seller on eBay that offered it for $11 shipped.
Edit.... I'm concerned now, the seller changed the pictures to a different dongle, when bought it from the seller I found on eBay, it had the pic of the dongle shown in the link above. Now it's changed and has the same model but different looking dongle, this might not be good!