Don't think so. I just set "never ask for a password anymore" to avoid to type in my lengthy password for each purchase. However, I can imagine if you have kids you prefer not to do so.
IMHO the combined intellectual force of Apple Design and the billion-dollar (bean) counters at Apple should have come up with a better solution, e.g. stick a TouchID sensor under the home button on the remote or somehow use an iOS device with TouchID to approve the purchase. They also could have used sending a 4-digit code to your iOS device to approve the purchase, way easier than typing in a 20 letter password using the touchpad.