For anybody that's interested, I solved a part of my earlier post. In RepositoryDashboard.ascx.vb, adding the highlighted line allows setting the font style for the DNN Tree.  However, I haven't quite figured out how to enable a seperate font style for COUNT (will make readability better, I believe).  If anybody takes this a step further and figures out how to enable a seperate CSS style for COUNT when used with DNN Tree, I'd be interested.  I'd also like to go with blue folders as opposed to the standard yellow but that's a low priority.

Private Sub lstObjects_ItemDataBound

Select Case aTemplate(iPtr + 1)
Case "TREE"
If Not m_hasTree Then
Dim obj As New DnnTree
obj.ID = "__Categories"
obj.SystemImagesPath = ResolveUrl("~/images/")
obj.ImageList.Add(ResolveUrl("~/images/folder.gif"))
obj.IndentWidth = 10
obj.CollapsedNodeImage = ResolveUrl("~/images/max.gif")
obj.ExpandedNodeImage = ResolveUrl("~/images/min.gif")
obj.EnableViewState = True
obj.CheckBoxes = False
obj.CssClass = oRepositoryBusinessController.GetSkinAttribute(xmlDoc, "CATEGORY", "CssClass", "SubHead")
AddHandler obj.NodeClick, AddressOf TreeNodeClick
Dim bShowCount As Boolean = Boolean.Parse(oRepositoryBusinessController.GetSkinAttribute(xmlDoc, "CATEGORY", "ShowCount", "False"))
Dim Arr As ArrayList = categories.GetRepositoryCategories(m_RepositoryId, -1)
oRepositoryBusinessController.AddCategoryToTreeObject(m_RepositoryId, -1, Arr, obj, "", bShowCount)
objPlaceHolder.Controls.Add(obj)
m_hasTree = True
End If

To be clear, I am attempting to edit the Folder icons as used in the Repository module...which incorporates the DNNTree.  RepositoryDashboard.ascx.vb is found in the Repository source code and the code retrieving the Folder icons is probably the same as in the DNN core/DNNTree code-behind. 

In the case of the Repository, I am sure that I can edit the Repository source code to call icons from a different location but haven't done that yet.  Aside from that, I am unfamiliar with any way to alter the icons used by DNNTree using an XML file or CSS.

If anybody does, two of us would be interested.