If you want to get white rims just for the hell of having white rims, try to paint them. It will save you money, and you can either do it yourself or get someone to do it for you.
If, however, you want to upgrade your kona for performance aswell, then i recommend you get a whole new wheelset, because the hubs that come stock on your bike are less than impressive. I would definitely not recommend getting them built up with new rims.
Halo Combats are good if you are on a budget, and you can get them in the colour you want. But you mentioned your wallet wasn't particularly heavy, and performance costs, so if I was in your position I would look into getting my current rims painted.
btw dont get white grips they will look good for like a day.. as for rims well if you are intent on getting white id go for syncros although they are pretty pricey. however if you are actually looking for performance you should definitely look into the sun rims mtx 4x. i ran them on my hardtail and did everything from dh to street i was verry pleaser with them and neve3r got any flatspots.
outlaws are only $250u.s. complete just save up a few more bucks and get those! and u can get them in all white hubs,spokes,outers. or black hub,spokes and white outers. http://www.cambriabike.com/shopexd.asp?id=68688&page=AZONIC+OUTLAW+DISC+MOUNTAIN+BIKE+WHEELSET