Frames are still available, mostly in red, on the website, so it should be possible to get a Sherpa for a while yet?? Tho' step-thru may be unavailable?? Worth checking. So if the frames are available, while still in stock, I guess Thorn would still build one up when they are fully working again?
I have a red Sherpa, flat bars, components tending towards lighter weights - a very nippy and secure bike, my preference over the Audax for urban riding - I've done several long tours on it too. I'll be sorry to see them off the list.
Lewis