Correct me if I'm wrong, but it's a SIT just a big power JFET? And I may be wrong, but I think IXIS makes some. I heard somebody talking about how to make a MOSFET produce triode-like curves at BA, but I can't remember who or when.SITs are something different. No-one makes them- it would otherwise be Big News.
I think it's safe to say, in any event, that if an amp sounds like this or that gain device, it's not a particularly exceptional amp.
I agree with your last comment; to me most transistor amps also sound like transistors. I've heard a few tube amps that sound like tubes- don't like that either. I like neutral.