It's a bit old now this question, but I came here via Google, and someone else might also. My solution was to create a Preflight profile (Acrobat 9 Pro) which errored on font information. Clicking on the font name in the results then jumps to the page and highlights the text. Downside is that you get a list of all fonts on all pages organised by page rather than by font name, but it provided a solution for me.

1) Create a new Custom preflight profile Advanced|Preflight|Options|Create New Preflight Profile

2) Give the profile a name (Fontfinder, say)

3) In the left window of the dialog click "Custom checks"

4) In the right window of the dialog below the blank box click the plus symbol to create a new check and include in current profile

5) Click "text" in the Group, the bottom property is "Text size". Select this and click "Add"

6) The pane below now has more options. Click on the drop down options probably labelled "equal to" and select "less than"

7) Enter a large value in the Number field. I entered 500

8) Top left of the dialog when check fires report as... and enter something like Text size 500 pt or less and click OK. There should be a new custom check in the pane with a red cross beside it. If the cross is not red, click on the check label, and select "error" below the pane

Repeat the steps above for another error check, but changing the option for 500 to "greater than or equal to", and Check fires report as Text 500 pt or greater

9) Click OK in the Edit Profile Dialog

10) Run the profile on your PDF

I set the font to error on a large point size so that all of the errors would report in a group. The second check is simply to catch any font larger than that. I suppose you could check for pt size 50000 and have the same result.

It is possible to remove all the fonts forming xml document type WordML.

<?xml version="1.0" encoding="UTF-8"?>
<?mso-application progid="Word.Document"?>
    <w:wordDocument xml:space="preserve" xmlns:w="http://schemas.microsoft.com/office/word/2003/wordml">
     <w:body>

      <w:tbl>
       <w:tblPr>
        <w:tblW w:w="9570" w:type="dxa"></w:tblW>
         <w:tblBorders> <w:top w:val="nil" /><w:left w:val="nil" /><w:bottom w:val="nil" /><w:right w:val="nil" />
         </w:tblBorders>
       </w:tblPr>

    <w:tr>
     <w:tc>
    <w:tcPr><w:tcW w:w="4785" w:type="dxa" /></w:tcPr>  <w:p></w:p>  </w:tc>
     <w:tc>  
    <w:tcPr><w:tcW w:w="4785" w:type="dxa" /></w:tcPr>  <w:p></w:p>  </w:tc>
    </w:tr>   

     <w:tr>    
         <w:tc>
          <w:tcPr><w:tcW w:w="0" w:type="auto" /></w:tcPr>  <w:p><w:pPr><w:jc w:val="right" /></w:pPr>
       <w:r><w:t>Company: </w:t></w:r> 
      </w:p>
     </w:tc>   

        <w:tc>
          <w:tcPr><w:tcW w:w="0" w:type="auto" />
           <w:tcBorders>      <w:top w:val="single" w:sz="2" w:color="0070C0" />    <w:left w:val="single" w:sz="2" w:color="0070C0" /> <w:bottom w:val="single" w:sz="2" w:color="0070C0" /> <w:right w:val="single" w:sz="2" w:color="0070C0" />
           </w:tcBorders>
          </w:tcPr>
         <w:p><w:pPr><w:jc w:val="left" /></w:pPr><w:r><w:t></w:t></w:r></w:p>
        </w:tc>      
       </w:tr>       
      </w:tbl>
     </w:body>
    </w:wordDocument>

But, even if you delete all the styles and fonts of the original document, Word will assign during the opening of the document style by default. Also, at least one font will be in the Acrobat document when you open it, as if you did not act.

Office WordML XML File, Word load default style:

After save as PDF in Acrobat view one font

A good solution is to choose at least one font that will still be in the pdf file and use it.

Way 2: Removing Unused Styles from Word

Sub DeleteUnusedStyles()
    Dim oStyle As Style
    For Each oStyle In ActiveDocument.Styles
        ‘Only check out non-built-in styles
        If oStyle.BuiltIn = False Then
            With ActiveDocument.Content.Find
                .ClearFormatting
                .Style = oStyle.NameLocal
                .Execute FindText:=””, Format:=True
                If .Found = False Then oStyle.Delete
            End With
        End If
    Next oStyle
End Sub 

See Format Fonts for Text Field Default Values

Style almost always includes the font and font size used for the determination of other sizes. Paragraph, line spacing, and so on ... If you need a different style mechanics generate the document itself. Including substitute fonts. If the final PDF document then use the built-in Adobe JavaScript. Or Adobe LiveCycle Designer ES and XDP XML.

Using Acrobat JavaScript in Forms: Importing and Exporting Form Data

XML Forms Architecture PDF!