I have been looking into CSS frameworks and in particular LESS (http://lesscss.org/) and Modernizr (http://www.modernizr.com/). LESS will soon be implementing a js version which is when I will start using it.
My question is would it be possible to combine these frameworks?
Use LESS for creating your style sheets and use Modernizr to check for compatibility and apply the results.
Anything's possible. Whether or not it's a good idea is another matter entirely, and it's pretty difficult to say anything about a future release which does not yet exist. All I can say for certain is that LESS chokes on a great deal of CSS syntax its developers have no experience with and as such isn't terribly practical.