CPU World published box numbers for the Core i7-3740QM and i7-3840QM, which will be positioned to support the current 2.6 GHz 3720QM and 2.7 GHz 3820QM models that are positioned on the high-end of the family.
There is not much room for clock speed tweaks for the 3740QM and 3840QM as the flagship model 3920XM already runs at 2.9 GHz. Still, it is pure speculation to talk about clock speeds at this time as Intel denied to comment on the unreleased CPUs. However, the 3840QM could ring in at 2.8 GHz.
While we agree that feature changes from the rest of the product family are somewhat unlikely, there is a reasonable chance that these two processors are limited production, on-demand SKUs for individual customers. Intel frequently offers special SKUs for large volume customers with special demands, such as Apple.