As random as this is, I'd kind of like to point out that "Thane" is a title more Gaelic in origins, and Thanes were in fact not the "servants" of lords, but landholders in their own right and pretty much equal to them. I believe in pre-Norman England and Scotland a Thane was similar to a Count and was outranked only by Dukes and Earls. That being said, I really like the idea of this sort of "vassal's vassal", I think it could be great if properly implemented.