Sound Practices Issue 6 (Summer '94) listed Wellborne Labs, Carey, Audio Electronic Supply (AES), Audio Note, and I think Bottlehead is in there somewhere. I don't know if any are no longer in business. Fi is gone, I think.The last Listener shows Marchand Electronics. The latest Vaccum Tube Valley shows S-5 Electronics advertising an SE kit for a hundred and forty dollars.
A web search shows Decware Zen as a kit.
I built Paramours which are in the process of going direct coupled. What a great learning experience. I'm now in the process of putting together a non-kit amp.
Hope this helps.