Hi, Paul, and welcome! There are a few other threads asking this same question. I'll see if I can pull a few for you to look at...
This light is quite cheap, and the light is already made. You could buy it, take a chance, and mod it with a different driver (or ask someone to) if it doesn't suit your needs. I don't know how bright it is, exactly. If you are not absolutely set on red, you can find a red-orange LED that may be brighter. According to
this there is a red Cree XP-E, and it is good up to one amp.
If you scroll to the bottom,
this page lists some SST-90 red LEDs, which will meet your criteria of being insanely bright, but will also blind everything it hits. Unfortunately, it also says no stock, but maybe you can use the part number to source one from somewhere else.
Good luck!