Not sure I can be of much help but I took a quick look around at “cyan” emitters in that wavelength spread. Looks like most of them are pretty low power and cannot handle much current or heat, so the design will need to accommodate that carefully with the driver, heat sinking, and perhaps a cooling fan. Osram has one that looks like perhaps the best contender as it has a wide viewing angle and is a little more robust (this is the 490nm peak…they may have other versions available as well…and datasheet is linked on this page for convenience): GC VJLPE1.13-KULR-36-1-700-R18 OSRAM Opto (ams OSRAM) | Optoelectronics | DigiKey
I don’t know about premade mcpcb’s but I think the first step is to try and decide how many emitters will be needed to give the output and spread that you want…may need more running them in open “mule” fashion like this with the added layers of light-reducing covers/filters, compared to a reflector/optic like we use in flashlights (I am assuming in this case that it would be desired to omit any optics that cover the emitter, since that would add an additional factor to light reduction and likely affect wavelength). Once you know that then you can see if any boards match your needs (need to pay attention to series/parallel of course, compatibility of the smd footprint for soldering, number of mounts, etc……might be simpler to just use single-emitter stars and place them around the platform as needed?)….and then choose your power source and configuration.
These are quite tiny chips…1mm or so. I see some other emitters in that range from Lumileds, DC Components, and Broadcom but I know nothing about any of those…nor this particular Osram really, but we know from many of Osram’s other emitters that they are generally pretty well made and consistent.
Here’s another possibility on Aliexpress….again, know nothing about the emitter (and although I’ve never used them, I’ve heard that this particular store is a decent one): https://www.aliexpress.com/item/32893943039.html There are lots of similar stores on Aliexpress that deal with “general led” stuff as opposed to flashlight-centric parts, and they’re more likely to have the range of mcpcb’s and perhaps drivers that you’ll want (maybe).
Another supplier there that may be worth considering is Tangsinuo. They specialize in filters and lenses, seem like a pretty professional outfit (that cannot be said for the majority of Aliexpress sellers….). If they don’t have a listing for something you want, it’d be well worth messaging them to see if they have it/can get it. For larger pieces it might still be price competitive with what you can get domestically even if they need a higher shipping cost for protection. https://tangsinuo.aliexpress.com/store/4314008
Also, you may find this other recent thread of interest…biologist exploring biofluorescence in the deep blue 450nm range: Help Needed: Cree XT-E Build for Biofluoroscopy