Another good reason for building diesel attack boats for that job, Jeff.
Given that the submersible is going to a) hamper the SSN in any other role (self-noise generated by turbulence around the attached submersible) and b) detach from the mothership like the Japanese Pearl Harbor midget-submarine flotilla, there's no point in tying up a full-sized, fully-fanged, super-stealthy fast-attack with the sneaky-pete mission. A Collins- or Yuushio-class boat (both have excellent endurance) would perform the mission just as well.
Deployment of numbers of diesel boats is feasible if a modest number of 25-kt, 2000- to 4000-ton submarine tenders were to be added to the OOB, to deploy with MEU's which would both screen, and be screened by, the diesel submarine flotilla. We probably still have hulls like that in the Mothball Fleet somewhere.
You also mentioned arming various small combatants with Harpoon, Standard, etc. Why would it not be preferable, when arming a ship with Harpoon, to install underwater torpedo tubes instead, and use the submarine-launched Harpoon, Exocet, Tomahawk, etc., variants? And reserve deckspace topsides for AAW systems? The new trimaran small-combatant design especially lends itself to this arrangement.
I know that they are using the new SSGNs to perform Littoral opertions right now...a 14,000 ton monster whose natural home is the deepest water available. But they built a huge SEAL capability into them. These DEs would be perfect for that at a lot less risk.
The SSGNs are GREAT because of their SLCM capability...but not, IMHO< a good idea for littorals.
I do indicate on those smaller vessels, inlcuding rhe LCS to install a MK-41 VLS> They are capable of it and both manufacturers have a mulit-mission version of the same craft with all of those capabilities. As they are, with the mission packs, they are, IMHO, severely underarmed when out on a miossion should they run into opposition that is not geared towards the pak they are carrying.