Hiyas Zalp:
Don't know if this helps or not, but since I don't have the Book of Hell, I took the time to look through some of the Infernum books, and maybe this will help you a little, course, you will need to have access to some of the Infernum books.
In Book 2 of the Infernum rulebooks, on page 102, it states "Nine great houses....9 princes of the pit..."
Elsewhere in the same book, on page 96, it refers to the Head of each House as being a minimum level 25 demon.*
So, if you are interested in stats for a Hellish Prince, you could use a level 25(25+) demon, and if you have book 1, you could generate one yourself. Book 3 also gives stats for some of the ruling heads of the houses. Currently my son has appropriated both books so I can't tell you much more ATM.
The biggest breakdown is that in the Infernum game, there are 9 great demonic houses vieing for control of Hell, thusly, 9 Great Dukes of Hell, not 4.** Once again through, that doesn't present a great problem, as there was a time in the Infernum's history when there were only 4 houses, and if the "vieing" for control the houses are currently engaged in reaches it logical end-point, there is sure to come a time when there are only 4 houses (or less) again.
Hope this helps a little.
Chaio
Mikeydanuke
* Technically speaking, a Fallen Angel or a Mortal Sorcerer could be the ehad of a demonic house also, but that might be more information than you need.
** Howeve, most of the houses would probably not really consider House Lictat to be a great house, and the less said about Glabretch the better....