Hi Johan,

The "magic" of the Icon Picker package is done by hooking up to the BaseTree.BeforeNodeRender event ... then checking the properties to see which icon to display.

Here's a quick-n-dirty code snippet...

namespace Bodenko.Umbraco.ApplicationEvents
{
    using System;
    using System.Collections.Generic;
    using umbraco.BusinessLogic;
    using umbraco.cms.presentation.Trees;
    using umbraco.cms.businesslogic.web;

    public class CultureIcon : ApplicationBase
    {
        public CultureIcon()
        {
            BaseTree.BeforeNodeRender += new BaseTree.BeforeNodeRenderEventHandler(BaseTree_BeforeNodeRender);
        }

        void BaseTree_BeforeNodeRender(ref XmlTree sender, ref XmlTreeNode node, EventArgs e)
        {
            if (node.NodeType == "content")
            {
                List<Domain> domains = Domain.GetDomains();

                if (domains != null && domains.Count > 0)
                {
                    foreach (Domain domain in domains)
                    {
                        if (domain.RootNodeId.ToString() == node.NodeID)
                        {
                            node.Icon = String.Concat("../path/to/images/", domain.Language.CultureAlias, ".gif");
                        }
                    }
                }
            }
        }
    }
}

There are many ways to do this ... my thought would be to grab all the domains, loop through them, if the (current) node matches the root node id, then change the icon.  Performance wise, this would need a some work ... it's not good to grab all domains per each node render ... so maybe another check to find out which level the node is at? i.e. level = 1 is the base/root of your site?

Let us know if you take this any further!

Good luck, Lee.