There is at least one out there now (someone posted it on a 190 page thread but I can't find it now).
Does anyone know what it is?
http://coinpayments.netDoes this really change alt coin --> USD instantly like bitpay?
No. They just give the same coins back, they handle the exchange rate(s) for you though, so sites can list in $ and take coins (that's why cryptosextoys has no fiat option and uses direct payment).
This wont happen because Bitpay uses Bitstamp (I think) to instantly place a sell order BTC -> USD then credits the merchant the USD. To do this you would need an ALT -> USD exchange that would be happy to process the sell.