Mark-
If your dataset is not too large, you could probably have an interactive
result set using "OR" conditions within a structured vocabulary. For
example, you can set some parametric ranges for price, some literal
values for land type, and require that the user specify one or more
unique values in the set to display over a scoped map, much like Yahoo
Maps.
If the dataset is too large, or if interactivity is not required, then
you could just use a standard query builder.
Maybe I'm missing some nuance, but the solution seems pretty
straightforward.
