I'd would bet that if we were look at the statistics of multitool owners we would find trends along these lines:
1) Most multitool owners will purchase a single multi-tool and they will look for one tool that fits all their needs, and will be of medium to small size.
2) Most Surge owners also own other multi-tools. The Surge they would use for heavy jobs, or for outdoor excursions, and they would carry another smaller multi-tool for daily use.
So I would surmise that the Surge itself is a niche product that doesn't have the mass market appeal of a smaller more easily carried tool. So the market for a premium Surge would be an even smaller market within that niche market. I still think it's within the realm of possibility that we will see a Surge TTi, because I believe the R&D costs associated with producing a product would be minimal. However I believe the premium for such a product would be an even higher percentage over the cost of a Surge than the cost of a Charge over a wave.
Just my opinion.