>> > Or we could have a user option to do that regardless of the argument,
>> > but then we should decide on which of the N new lines to put point:
>> > the first one copied or the last one.
>>
>> A user option looks preferable.  In case of a prefix numeric argument,
>> it also makes sense to have 3 choices:
>>
>> 1. leave point on the old line
>> 2. move point to the first new line
>> 3. move point to the last new line
>
> Patches welcome, but if you want to have this in Emacs 29, please
> hurry up with the patches.

This is both simple and general allowing to specify any number
for the new line position counting from the first/last line,
but only values 0, 1, and -1 are really useful: