Something very similar to this has in fact happened in the real world.
So yes, it is totally feasible.
This is essentially how saga-period Iceland worked. Free men owned their own land, and generally supported themselves as farmers. The equivalent of a "lord" (a gothi) was not a land ownerowner[1], but someone whom you would contract with to provide taxes or service in exchange for protection and legal representation--and while it might be convenient, there is no actual need for the effective domain of any given gothi to be geographically contiguous.
Being a gothi came with obligations to provide, e.g., a meeting hall for public events, to arbitrate legal disputes, and to represent his constituents in parliament. Like a lordship, the office of gothi was heritable, and there was a limited number of them--you couldn't just make yourself a gothi by getting rich enough. Unlike a typical lordship, however, the right to the office could also be bought and sold.
To the best of my knowledge, there was no extended hierarchy in actual history--gothar reported to the Allthing, and that's it. But I see no particular reason why a similar system couldn't allow for lower-level nobility to contract with higher-level nobility in an arbitrary number of levels, just like feudalism.
[1] Or rather, was not the owner of the land you lived on; not a landlord. He almost certainly owned his own land to farm, just like his clients.