Hi,
Welcome. Ooo, CSS3, very slick, and a very pretty site.

Yes, that should be very feasible. You need to template the calls. See this for information:
http://muddydogpaws.com/development/wayfinder/parameters.html
At a glance, I’m thinking you would need these parameters:
for &outerTpl that makes the CSS3-y container:
<nav>
[+wf.wrapper+]
</nav>
For &parentRowHereTpl, giving the non-link:
<li[+wf.classes+]>
<a href="#">[+wf.linktext+]</a>
[+wf.wrapper+]
</li>
For &innerTpl, making initial children invisible before clicking fires JQuery:
<ul style="display: none;">
[+wf.wrapper+]
</ul>
The templates are chunks, and they’re referred to in your call, as you’ll see in the documentation link above. That should get you started. Not sure if you’d need an &innerRowTpl, default might work. This is all Evo code, placeholders in Revo are different, I believe they look like this: [[+wf.wrapper]]
Beyond that, you’ll obviously need to include your libraries for the making the items slide down. I might try this on a site myself!
Cheers, Dave