In Europe, the vast majority of the ruling class is composed of Those Who War. Men who hold manorial lands (which are composed of peasant villagers who pay rents in goods and labor, along with associated manorial rights and the related fines) in exchange for the service of men wearing mail and riding large horses. However, there are plenty of variants and situations where a noble might hold ruling status without holding any manorial land.
So my question is, would the Landed Noble virtue apply to a noble whose wealth (every bit the equivalent of a banneret's) came in the form of rights and offices that don't include land? For example:
*A Spanish hombre with a right to tax a city?
*A Muslim emir whose income comes from farming port duties?
*An English sheriff (of noble ancestry and knighthood) with no manors but a whole lotta fines coming in (when that green-hooded poacher isn't stealing them back)?
*An Italian patrizio?
*In a pre-1204 or post-1261 saga, a Byzantine aristocrat who has secured offices (and the wealth accruing to them) but no personal landed estates?
Personally, I'd say yes to the first two (assuming the emir is expected to provide military service), and that Italian patricians should use C&G merchant Status Virtues, but I don't know what virtue I'd use for the sheriff, and especially not for the Byzantine aristocrat.
I'm not terribly sure about the others, but let's clarify what an Italian patrizio is. Many self-governing municipalities or aristocratic republics (Venice and Genoa being prime examples) were ruled by councils of clans, extended families whose nobility derived not by a higher authority (as in feudal systems) but simply by having been one of the ruling clans of the place for a ... sufficient amount of time. In this sense many considered feudal nobles of other parts of Europe, even powerful ones such as dukes or earls, as socially inferior, since they were beholden to some other individual. Any member of such a clan would be a patrizio; but of course the power held by the clanhead would dwarf that held by a young granddaughter.
So, the "average" patrizio would be a Gentleman/woman. An important member of the clan, who has some serious weight in the clan's policy but who's not the clanhead, would probably add Temporal Influence. A clanhead would indeed be the equivalent of a Landed Noble ... or even a Great Noble (as per Lords of Men, worth one or two Major Virtues depending on how central the character is to the saga): the clanhead of a major Venetian family, say a Dandolo or a Partecipazio, is certainly at least the equivalent of an English Baron in terms of power and influence. I think in this sense being a Landed Noble is a better approximation than being a Capo, but with a crucial distinction: as a patrician clanhead you do not owe service to a greater noble or a king, because there is nobody above you in the hierarchy, only a council of peers.