I was thinking more of the lines that the Malachor V skybox is animated - and it show lightning flashes in it. If you're thinking about adding day and night cycles, how will you deal with having lightning occur during the day. Also, does Malachor V even need a daylight cycle as too much light might spoil the spookiness of the set.
As of 28APR13: I released a new small texture mod! Check it out here