The trick for me here is that it requires all levels ul/li to have unique id's. This is where I have become lost.
[[!Wayfinder? &startId=`0` &outerTpl=`menuOuter` &rowTpl=`menuRow` &innerTpl=`menuInner` &innerRowTpl=`menuInnerRow` &hereClass=`current_page_item` &firstClass=`` &lastClass =`` &levelClass=`level` &innerClass=`submenu` &rowIdPrefix=`m` ]]
&rowIdPrefix default: FALSEYou will need to have custom rowTpl and innerRowTpl chunks with the [[+wf.id]] placeholder added. Just copy the default tpls and add the placeholder where you need it, in the li tags or the a tags.
values: name of prefix
description: If this parameter is set, Wayfinder will replace the placeholder [+wf.id+] with a unique id consisting of the specified prefix plus the document id.
example: &rowIdPrefix=`topMenu` will output the following for doc # 29: id="topMenu29"

<ul id="main">[[+wf.wrapper]]</ul>
<li [[+wf.classes]]><a href="[[+wf.link]]" title="[[+wf.title]]" [[+wf.attributes]]><span>[[+wf.linktext]]</span></a>[[+wf.wrapper]]</li>
<ul id="[[+wf.classnames]]">[[+wf.wrapper]]</ul>
<li[[+wf.classes]]><a href="[[+wf.link]]" title="[[+wf.title]]" [[+wf.attributes]]><span>[[+wf.linktext]]</span></a>[[+wf.wrapper]]</li>
[[!Wayfinder? &startId=`0` &outerTpl=`menuOuter` &rowTpl=`menuRow` &innerTpl=`menuInner` &innerRowTpl=`menuInnerRow` &hereClass=`current_page_item` &firstClass=`` &lastClass =`` &levelClass=`level` &innerClass=`submenu` &rowIdPrefix=`m` ]]
default: NULL
values: name of class
description: The levelClass will be applied to each item denoting each items level, the level number will be added to the specified class (i.e. level1, level2, level3, etc...)
<div id="menu_container" style='display:none'>
<div class="nav_block">
<ul id="main">
<li class="level1"><a href="#" title="" ><span>Home</span></a></li>
<li class="level1"><a href="#" title="" ><span>About</span></a>
<ul id=" "> <--- THIS IS WHERE innerClass works but I must have unique anything here..??
<li class="level2"><a href="#" title="" ><span>Overview</span></a></li>
</ul>
</li>

#column1 ul{background:green;}
#column2 ul{background:yellow;}
#column3 ul{background:red}ul {top level css...}
ul ul {second level css ...}
ul ul ul {third level css...}@ringmaster
Hi Roland, Did you find a solution to this? I'm facing the same issue. See my post here:
http://stackoverflow.com/questions/18580518/modx-revo-wayfinder-3rd-level-ul-different-to-2nd-level-ul
Any help greatly appreciated!
Craig