Cheap and reliable single color LEDS for 0.25-0.5W output?

I'm trying to make a LED light source that comes close to natural sunlight, and has a high CRI. Total power will be in the 5W range.

I'm going with underdriven 3W Cree or Luxeon white LEDs for the bulk of the light output. That's the easy part.

It's the supplemental colors to fill in the spectrum that has me confused. I need only around 0.25W-0.5W each of 470nm (blue), 505nm (aqua), and 660nm (deep red). It would be wasteful and expensive to use top-quality 3W LEDs and underdrive them by this amount. Neither do I want to use dozens of tiny 10-20mw LEDs. And that's the only two options I'm currently familiar with.

What's in the middle of these two extremes? Are there any good quality name-brand 0.5W-1W LEDs providing these colors? Or if I buy cheap no-name 3W LEDs and drive them at only 0.25W-0.5W, can I expect most of them to last 10 years without losing significant output?

I have a few old Cree XL4550 1/2 watt leds in r,g,b,a on star PCB if you want to PM me

WeLight said:

I have a few old Cree XL4550 1/2 watt leds in r,g,b,a on star PCB if you want to PM me

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I'm going to be using these to light a planted aquarium, so many will be needed. And if successful, I'd like to use the same design for a few more aquariums, so that would require a continuing source of parts. Thank you very much for the offer though!