Of all amendments, I think ones to limit term and impose a Code of Ethics has the most chance.He's going to need 2/3 of both houses of Congress and 3/4 of the state legislatures to approve his amendment. There's no way on God's green earth that will happen.
Limits on who can be on the court and how long they serve should be there. There should be a minimum age, and a minimum amount of time on the bench. The current trend on appointing ever younger members because they'll be there with their agendas longer is not good for the country.
\having set minimum qualifications, I think the court should be expanded to 11, and always have 1 from each circuit. You then go for an 11 year term limit. That means every president replaces 4 Justices during a term But must choose from the Circuit the retiring one comes from.