A lazy-chain for std.range?

[Mint via Digitalmars-d]

So, I noticed that one way I frequently use the chain function 
defined std.range is as sort of an else-clause.

ie.

   return elements
       .map!( . . . )
       .filter!( . . . )
       .chain(fallback.only)
       .front;


After transforming and filtering elements, chain would 
effectively append a fallback element to the resulting range, and 
then the first element would be taken. Hence if the result of 
filter (or the initial range) was empty, the result would be 
fallback.

My concern is that in some cases my fallback is expensive to 
compute, and acts as a performance sink.

I'm wondering if about the possibility of having a similar 
function that took a range as a lazy parameter. Specifically, a 
the parameter would not be evaluated unless one of the resulting 
range's functions were called. Thoughts?