Yes there are now a lot of options out there. - I have implemented this design on www.skinningtoolkit.com using the housemenu, BUT it is quite complicated and takes a bit of programming various menus (think there may have been 8 separate menus across the various skins - but they look like one menu).
You can look at the css code from skinning toolkit to see how I have set this up and this tutorial:
How to create Horizontal CSS menus in DotNetNuke using the HouseMenuoutlines the technique that I used with the house menu - even though it's for horizontal menus it applies to how you need to configure your vertical menu.
- The other option would be to check out the snapsis menu, I haven't had chance to look at it yet but it appears as though it has a lot more flexibility in terms of configuration options so you maybe able to set this up without jumping through as many hoops when using the house menu.
I hope this sends you in the right direction,
Thanks,