Yes, it would not actually be too hard to do. It is only the initial setup that would have to change, and then the rest of the game plays in exactly the same way. I vaguely remember what zaps I had to make to get the trial game set up, so it could be done. But I am hopeful we are making progress on a map-making replacement so don't give up on new variants! Of course, we need the 'new variant voter' process to run again that Pedros runs so I know which one is next.
However Shift Right/Left would not be too bad. It would have to be an option like Stuff or Fog, and then it could apply to any game....oh, except for non-standard start games like Chaos. Not sure Chaos Shift Right makes a lot of sense! I guess the question becomes whether we want to add what is likely to be a relatively rare option and take up another possible 'options' slot

. The issue with options is that every time we add one, we make things more confusing for players wanting to join a game because there are more things they have to check.
I'll tell you what I had though of at one time. Not sure how much sense it makes, but anyway. After the first Shift Right game, a number of players said they would love to play another one some time. I wondered if rare 'tweaks' like this might be something that could happen on an occasional basis - so for example every now and then I could create a Shift Right or Shift Left or Shuffle game and advertise it on the forum with a password for people to join. Then we don't have to add new and possibly confusing new options but people get a chance to get a fix on something a bit different now and then.
Anyway, as far as the original suggestion is concerned, if people think Shift Right is a good priority and a good use of limited options, it can certainly be done. Where it lands on the priority list will depend on how much support the idea gets