> Is there any way of achieving that now (using Saxon in my 
> case) without using a custom resolver?

No, it needs a custom resolver. The simplest is probably to use the standard
collection URI resolver to return a sequence of URIs of the selected text
files, and change the URIResolver to process these URIs by returning
text-only XML document nodes.
> 
> Is it likely to make it into the language?
> 

No plans, but you can always ask. It's always useful to describe a use case.

If we're going to do anything along these lines, then I think it would also
be useful to do something to "bless" current interpretation of the
collection URIs so that applications are offered some level of
interoperability.

Michael Kay
http://www.saxonica.com/