I use dotless 1.3.1.0 compiling less-files. This worked fine with bootstrap 2.x, but after switching to bootstrap 3.0.0 (downloaded the source from here: http://getbootstrap
After spending hours on getting this to work myself i found that dotless is quite useless at this time.
but here is where you can impliment Less and Bootstrap 3 Less in your mvc ASP.Net Project
http://www.tomdupont.net/2013/10/bootstrap-3-less-bundling-and-aspnet-mvc.html?showComment=1386250367416#c1439130135847828203
This guy just won an internets in my book and if you can track down his stack exchange account for me let me know.