Is there some way to define an input key such that I can use greater-than and less-than operators on it?

Something like the following:

select * from users where age > 15 and age < 30

would translate to:

http://service/airports?age_min=16&age_max=29

Perhaps like this?

<key id="age" type="xs:integer" paramType="query" gt_suffix="_min" lt_suffix="_max"/>

And a floating point version as well with some way to define the fuzz factor for the <= vs < case.