Generally, Ray guards Kobe very well. However, if there's a repeat of last night -- when fouls that are *never* called in the NBA are consistently being called -- then yeah, it makes sense to have Paul slide over and guard Kobe, and for Ray to guard Artest.
The only major threat there is that Artest will post up Ray. However, I haven't seen a consistent post game out of Artest, so I'd take the chance, and adjust to it if it happened.
We absolutely need to keep Ray out of foul trouble. He's a key to opening up space for both PP and Rondo.