Barbless,
Yeah, the coloration looked great to my eyes, that purple hue is something I have only seen in post spawn fish. Personally I love that coloration. But a lot of people may have expected a big wild brookie to have the classic gorgeous orange belly, and I didn't want that argument to get started.
WT2, I bet some Big Spring regulars have seen or caught several in this size range. Any other stream though, yeah, this would be completely unheard of, and maybe as rare as the wild tiger like you said.
I've spent enough hours fishing for wild brookies in general to have earned a really nice fish...but I've only spent about 3 hrs total on Big Spring over the course of two quick trips, so I was shocked to catch one of the bigger ones in there. It's not like I could take all that small mountain stream experience and apply it directly to a heavily pressured, flat spring creek.
I think it would be really incredible if we could rehab some more limestone springs back into native brook trout waters. There's probably like 5 in the whole state. Seeing what Big Spring is, it's sad that similar potential has been totally wasted (or is a great brown trout fishery) in the rest of the limestone regions.