Join the club. If the wheels are more than five years old you won’t be able to get a new rim as Mavic don’t keep spares. I have some old Ksyrium SLs with a worn-out rim and couldn’t get a replacement, plus the spoke nipples are all rusted solid. By studying the Mavic pdfs I worked out that the newer Elite rim is, as I suspected, identical to my old SL with just a difference in paint so I got an Elite rim from France, along with 20 spokes. It’s more about beating the stupidity of the Mavic policy; I don’t want to throw away a perfectly good hub for want of a rim. (I have always taken care to maintain the freehub and keep it well oiled so it’s not worn and nowhere near failing with the dreaded Mavic howl of death).
Tomorrow I have the 3-month x-ray and meeting with the consultant and if he tells me he succeeded in waking up the broken ends of my collar bone and they are growing into the graft material I’m going to mark my resumption of life as a cyclist by dismantling the old wheel and starting the rebuild with the new rim and spokes.