Requirements:
 Assumption:  Input file  = standard XML file {e.g http://www.w3schools.com/xml/note.xml}
 
i) Enable user input of custom XML page by provision of web address url to an XML page (in similar fashion to feed; but it is not a feed)
   Possible enable user input via browser paste (thoughts for/against welcome)
ii) Primary parse to display and allow 'deselection' of fields from XML import that are not required (by default, or set default to 'select' required)
iii) Import XML (with additional parameters set in ii) to [custom] node type
iii) Enable edit of imported node list (such as deletion of non-required records from list - can/may arguably be done with content listing by type)
iv) Enable linking of key# data field in XML import to key# data field in existing nodes (of type) for duplicate identification and/or replacement [or default global replace - achieved by relevant call to drupal].
 
My findings suggest that:
- there is nothing currently available to import XML pages with custom data sets
- there are some that require same
- CCK and Views may be suitable to help make this a generic contribution by way of creating destination node type? Also 'know of node import' but not yet investigated relevancy
  (question to note - if use CCK do we have access to data [ie is it stored seperately?] in DB for later export or additional requirments?)
- there are some existing API's for RSS/XML but I'm not sure if anything of use for this application
- there is some 'Google SUmmer of Code' work to look at feeds; but I do not think this is relevant.
 
I have not developed anything custom for Drupal for a couple of years and find the mix of contribs in this area 'confusing' so please lend me your wisdom:
 
- any suggested approaches to re-use existing API's and contributions
- any existing projects underway that this might impact or work with
- any willing developers / helpers /shadowers to help ramp up and/or to build a module for this
 
Additional Comments:
This capability would be great for commercial applications.
If I do this it is likely to be in the near future and to customer time constraints I would be happy to contribute back to drupal.
As you can see this i not specd yet but these are my ideas so far based on my client requirement and 'quick' initial look at available options
Any head start with better approach, where to look, who to talk to and what to research to measure viability/effort required would be very welcome indeed.
 
regards
 
Chris.