Im really not the right person to ask, i dont follow that so closely anymore. If you just want straight white you can do Bridgelux or samsung branded strips. I know
@Jonesfamily7715 recently did a diy based on arrow components; maybe they have a better grasp on where price and performance meets best. Seoul semiconductors may be a good cheapo option.
If you want something with fancy monos and spectrum tweaking check out cutter: they can usually make a strip you like; they carry almoat all spectrums and have a great range of prices. Their web can be a bit confusing, id try to contact them if you are after something special you cannot find there, or if you wanna see if they can do better prices. Ask for their first buy discount aswell. Maybe they even give you a forum discount for mentioning riu. Youll have to check with them.
Theres also GLA which makes fantastic crem de la crem products, top bin nichias with real efficiency tests, higher performance seal (you can hose down the lights, burn sulfur etc) and a real high performance full spectrum all the way from 400-730+ nm. They are really good guys, also do some discounts for amounts and forum; sadly not here anymore but you can find them on icmag or just by contacting them directly. Welcome to say hi from me if u go that way but they are not really midd range.
Why do you wanna diy? To save $ or something different?
What space you wanna cover? Flower/veg or full cycle?
Do you have a budget?
It helps you if you give or at least knows the answer of these questions going into this.