Oh Dear, still thinking toobs are where it's at?
BLF188XR has been around for a while now but yet no one has even mentioned it?
I've no idea why folk would use a tube amp anyway, nostalgia?
Even the 188 is a tad 'old hat' with more powerful devices running at 60V around now, however the 188 built up on a Cu spreader is available on eBay, just add LPF and drive with 3W.
Why use anything else?
Str.