Enumservices categories (COMMON, X-, P-, ...)

Hi,

While reading RFC3761bis and writing the IANA registration 
procedures, some idea crossed my mind:

To fulfill all the (known) requiements of Enum users, it make sense to 
split Enumservices in different categories. So far I see a need for three 
of them:

1. Ordinary (COMMON) registered Enumservices:
    - Normal IANA Registration procedures apply
    - No prefix

2. Registered Enumservices for Trial/Experimental:
    - IANA Registration procedures for Trial/Experimental apply
    - Prefix: 'X-'

3. Private Enumservices:
    - Not registered anywhere
    - Prefix: 'P-'

The last category would not need any special standardization document, as 
IMHO a short definition in RFC3761bis about usage of "P-" in private 
environment is sufficient.

Anybody second this proposal?

Objections?

cheers,
  Bernie