The only hip hop that I've heard being mixed with dnb and sounding good are these two tracks being mixed by Rich Reason at Hit and Run in manchester.. Like people have said above though It can't be that hard to beach match tunes if the bpm of dnb is just double time.. Hope this helps
Mobb Deep - Shook Ones Pt. 2
origin unknown - valley of the shadows
Why dont you try a hip hop instrumental, put a hip hop accapella over it, then cut out the instrumental and bring in a drum n bass tune under the accapella.