Done. If anybody can improve it, please post your changes...ig, can you include this in your next release :p

Note: requires that you actually set a unique datakey in your code...can easily be changed to look at tags...just use getTag() instead of getDataKey() (further to that, any property of a node!)...and perhaps then add them to an array or something...

function igtree_getNodeByDataKey(treeId, dataKey) {
    ///<summary>searches a tree and returns a node based on dataKey. Remember to enable DataKeyOnClient in control.</summary>
    ///<param name="treeId">the unique ID of the tree to search</param>
    ///<param name="dataKey">the dataKey of the node to find</param>
    ///<returns>webtree node with the passed in dataKey</returns>
   
    // a few simple checks...
    var tre = igtree_getTreeById(treeId);
    if (!tre) return;
    var nodes = tre.getNodes();
    if (nodes.length === 0) return;
   
    // new object
    var searcher = {};
    // store what we are looking for
    searcher.target = dataKey;
    // compare function
    searcher.compare = function(node) {
        if (node.getDataKey() == this.target) return node;
    }
    // recursive loop function
    searcher.iterate = function(node) {
        if (this.compare(node)) return node;
        if (node.hasChildren()) {
            var children = node.getChildNodes();
            for (var cid in children) {
                //if (this.compare(children[cid])) return children[cid];
                var result = this.iterate(children[cid]);
                if (result) return result;
            }
        }
    }

    // start the whole process
    // -- searching
    for (var id in nodes) {
        var result = searcher.iterate(nodes[id]);
        if (result) return result;
    }
   
    // nothing found...
    return;
}