not too familiar with plextor drives but from my experience the front covers of cd drives are just plastic that you can easily just snap on and off. i had a white cd-rw drive which i took apart and spray painted black and gray. good luck.
i'm not the krylon master either but what i've found gives the best results is even strokes from side to side. don't just spray, spray, spray. hold down the nozzle with even pressure, swipe over one side, and release the nozzle. now do the same in the opposite direction moving the paint slightly lower than the first swipe. i tend to get good results with this method. for about $3-$4 you can buy a can of spray paint and a piece of modelling wood and practice your technique until you are comfortable.
Best price I found on black Plextor CDRW drives was over at www.newegg.com. http://www.newegg.com/app/ViewProduc...ry=1323&DEPA=1
$152 + s/h for the 40x model which is in stock, they also have a 24x version but it's currently sold out.
There is also an Aopen 24x model with black/white covers included for $55 or a 40x Teac for $104.
I like the Plextor brand though for $104 the Teac is a hard price to beat for a drive of similar quality. If I only used the drive occasionally I'd probably just go with the Aopen model to save myself some money. Good luck!