RMSh tracks that fit Tamiya's T-55A kit?

I would say have a look at Trumpeters T-72 tracks. Their T-55 Omsh tracks fit perfect on my Tamiya T-55. But yeah, a replacement sprocket will likely be needed.

Sector 35 makes a pre-assembled metal RMSH track set:

https://hobbyterra.com/product_info.php?products_id=4258

Pro:  Pre-assembled tracks mean minimal assembly.

Con:  The people assembling the tracks have CA glue all over their fingers.  Since CA is clear, you can't see a thing at first.  But if you use a blackening fluid, the CA smudges on the tracks will prevent the areas from changing color.  If you paint your tracks, no biggie.

I have used Sector 35 tracks on several Tamiya tanks (Churchill, Cromwell, IS-3), and they all fit with no mods to their sprockets.

HTH and good hunting!

I've actually got some sector35 RMSh coming (eventually...)  I've used for some other kits and they're great. Have you used on the T-55 kit?

I've got some CA remover handy, that's good to know though. I've not had issues quite yet but thanks for the heads up!

I actually do have a Sector 35 RMSH track set and a Tamiya T-55, but they are just stowed away together in the stash.  I have not checked if the tracks will fit the kit sprockets.