Yes its called the 24ADAT i/o plate - you can get it on a new Pulsar or SCOPE card, not sure about swapping I/O plates on Pulsar1 & SCOPE1 though, never done that.
I have a Pulsar I, SRB I, Luna II, I wonder if the 24 plate would work for me. I wonder how much it is. I wonder if I have a space in the back for it. I think I ran out.