If you want to add LEDs (my choices at least)....
If you want to spend a little more and get LOTS of blue, buy one of the actinic kits from rapidled.com or reefledlights.com. both are similar in price for CREE leds. Rapidled just came out with a DIY kit that is specific for actinic supplementation, but reefled lights allows you to purchase all blue LEDs in all of their kits.
If you want to go a little cheaper, Stevesleds sells his chips for 1/3 of the price of CREEs - yes they dont put out as many lumens (90 v. 107), but since you arent replacing your light and are just going for the effect, they are a good alternative.
I wanted to add actinics to my RSM 130, but wanted to go the really cheap route - i got a blue LED strip from ledwholesalers.com - ended up costing me $25 with shipping and tax +a spare 12V DC wall adapter i had lying around. for an 8 watt strip thats about 16" long, it does a good job. i can tell when it is on with my 110V fluorescents on and it gives me dusk/dawn affect i was looking for (as well as bringing out the sick neon colors of my coral!)
You can always go with stunner strips or exotics (check out marinedepot) or whatever which are all good products, but for the price there are better options to a) ease the expense on your pocket book, b) meet your design constraints, and c) give you more stuff to play with
good luck with the mod