Sacrificing a chunk of that precious spectrum is huge though. Is LTE flexible enough to run some form of on-demand TDM between multiple base stations on top of it? Can it operate smaller cells on the same channels within the range of the larger cell, forcing the smaller cell to make do with other parts of the spectrum while the larger calls dibs?

Afaik older cellular protocols were relying on zero overlap between base stations serving the same frequencies, leading to a nice coloring problem that would seriously suffer if someone tried to fit in LEO cells.