Does Rick Steves tours offer a Scotland & Ireland tour?

Doesn’t look like it. Best to ask the Rick Steves crew directly. You can book back to back tours though.

https://www.ricksteves.com/tours/2024-tours

As far back as I can remember, they have always been separte tours. Many, many years ago Scotland was part of a tour that included England and Wales, but that one hasn't been offered in years. Perhaps you can look at the separte tours and do them back to back.

No, he does not have a combo tour.

I've done both the Best of Ireland and Best of Scotland which were each 2 week long tours. There is so much to see in both countries that I think it would be shortchanging to do a tour combining both as most of Rick's tours are a max of 2 weeks. He does have a few longer - Italy for 17 days and a Best of Europe tour for 21 but none longer than that. He does offer 7 and 8 day "heart of" tours for Ireland and Scotland respectively.

all their tours are listed here, on this page. At the link called "Our Tours"

Here's a shortcut: RS tours

What you can do, if the timing works out, is to do two tours back to back, one in Ireland and the other in Scotland. maybe requiring a day or two on your own between them. Up to you to work out the transportation,

It is probably too much to combine into a single tour as there is so much to see in both countries and you end up short changing both if you try and cram them both into a two week trip.