A number of business areas I work with use a folder structure to organise their Sharepoint housed documents (not ideal I know, but we\'re stuck with it).
I would l
With Sharepoint Designer you can edit the CAML of your XSLT List View.
If you set the Scope attribute of the View element to Recursive or RecursiveAll, which returns all Files and Folders, you can filter the documents by FileDirRef:
MyFolder
This returns all documents which contain the string 'MyFolder' in their path.
I found infos about this on http://platinumdogs.wordpress.com/2009/07/21/querying-document-libraries-or-pulling-teeth-with-caml/ and useful information abouts fields at http://blog.thekid.me.uk/archive/2007/03/21/wss-field-display-amp-internal-names-for-lists-amp-document-libraries.aspx