I don't know of any lakes in Indiana that produce the sizes that Clear Lake did except for Lake Michigan and the St. Joe when the steelhead run. I think you have to drive to Michigan for any chance at bigger inland trout in lakes. Ironically Michigan has cut way back on stocking browns in it's inland lakes and is putting them primarily into Lake Michigan and Lake Huron or in streams and rivers. Some of the mainstay lakes like Crystal and Higgins and others haven't been planted with browns for at least a decade according to their online stocking records.
My source for my trout eggs last December says Tiger Trout (Brook X Brown trout) are tougher than even browns when water quality gets tough but won't grow or gain weight until conditions improve. Read an article by a prof in NY that said tigers are tougher too. I want to believe them, but it seems counterintuitive as they are partly brook trout, which are the most sensitive of brook, brown, and rainbow trout when it comes to water quality. That said, I do know brook trout are tougher of the three when it comes to low Ph. But that's not is issue in our area as are Phs are on the basic side of the Ph scale. And our alkalinity is high enough that drastic Ph changes just don't happen.
I don't see money as an issue if they wanted to try tiger trout. It's just a matter of purchasing the eggs which they already do. If I was a biologist I wouldn't give up on Clear Lake. I would plant some brown trout experimentally. Was also told numerous northern pike may be part of the problem on Clear Lake. The biggest pike over the years I got into mount came from lakes planted with trout.