Growing a clone of Uchiha Itachi through genetic cloning and implanting the appropriate memories could resolve Uchiha Mikoto's worries. Moreover, the clone's memories would be controllable. In other words, Karn could give Uchiha Mikoto a perfect son, complete with Itachi's memories from the past dozen or so years.
Karn was utterly unwilling to save Uchiha Itachi outright, so he could only use cloning technology to fulfill Uchiha Mikoto's request. However, he would certainly have to conceal the cloning. Uchiha Mikoto should be perfectly satisfied as long as she had an Itachi who knew to repent.
When the time came, Uchiha Mikoto would surely believe that Karn had sent a clone over and secretly saved Itachi, when in fact it was the reverse.
"That's how it will be, Madam Mikoto. But Uchiha Itachi will have to live in seclusion somewhere in the shinobi world from now on. You'll only be able to visit him when you have time. Madam Mikoto, are you listening?"
Uchiha Mikoto lay in Karn's arms. As he stroked her slightly swollen belly, he explained the somewhat modified plan to her. Uchiha Mikoto was a little distracted, and only came back to herself after Karn called her twice.
"Wh-what is it, Lord Daimyo?"
"What do you think of what I just said? If you have no objections, let's do that. You'll just have to treat Uchiha Itachi as dead from now on. As for Sasuke, it would be best to wait until he's grown up before telling him."
Uchiha Mikoto could vaguely recall what Karn had said. She had been too comfortable and exhausted just now, leaving her somewhat distracted.
"L-let's do as you say, Lord Daimyo."
Uchiha Mikoto could not think of anything better, either. Besides, the hand on her belly gave her a tingling sensation that