Aye you could convert a 2600 from something english (hell a 2700 exists RTR from Bachmann) but an ICR is unlike anything in the UK as far as I can see, it would be very hard to scratchbuild.
plus they have unlimited route abalibility. I think only places like ballina, and maybe the ballybrophy line have have not had a 22k yet. Middleton and cobh lines have got 1 or 2 on railtours. these are very much the face of Irish rail outside the cork and northern mainline for the most part (and even then ICR’s can be found on them)
I love the 2600, the best of the 2nd generation of DMU’s. But there not really as well travelled. And in 2022 they barley leave cork and never leave Munster. actually a good article on them here recently. I love the new livery but the as deleived orange with points logo is probobly the nicest
https://www.tailtetours.com/post/the-2600-class-the-railcars-that-keep-on-going