This is a good but not great way of doing a noble multi-class only class. By making noble a class you dabble in, any character class can be a noble. This is a great design goal but the implementation is unfortunately lacking. Weapon based characters are much better represented than implement based characters. The level of disparity in power a Noble Fighter would have over a Noble Cleric for instance is a bit jarring and detracts from what would otherwise be an excellent product. Also, the non-weapon powers don't have the implement keyword although adding that as a houserule is easy enough to do. The Paragon Path and the DM Noble templates are very good.
[4 of 5 Stars!]