Hi,
Designation hierarchy cannot be created in isolation, it has to be created in alignment of the organisation's structural approach. Also several other aspects like employee developmen path, other factors and criterion's like experience, education also needs to be kept in mind while going ahead with the designing the hierarchy as to which particular criteria to be made as base for drawing hierarchies.
If the organisation is following flat structure than Broadbanding would suffice and other wise you are free to design and incorporate the designations as per the current and future workforce and meeting their professional aspirations.
It goes without saying a thorough homework to be done before proceeding with it as a wrong structure would disturb the organisation culture. I have enclosed one attachment i came across on web. Hope it will be of any help to u. Also you can get lot of references on the net all you need is to search them.
Regards
Meenakshi