How could I go about making a menu like this one (http://bootsnipp.com/snippets/featu...vbar-menu) or who could I contact to help with this?

I've tried to manipulate the bootstrap menu .xslt file myself with no luck.

I would recommend that you reach out to an specialized developer like Armand Datema - He can be found @ http://www.2dnn.com/

He wrote some extensive articles about the topic of manipulating .XSLT files as you can find @ https://www.dnnhero.com/Listing/pfauthid/2/Armand-Datema