Smart buying buying a preamp with tubes anot avail except as made by preamp manuf?

Op, if you are interested in some informed comments state particulars so everyone knows what manufacturer, what preamp , what tubes etc. 

It might be amazing. With spares, it could last a lifetime. Small signal tubes (can) last a long time.

My luck. I buy one with a spare tube. Then someone else buys all the rest, all 15 units.. all 30 tubes.. Sounds like a nightmare. to me.. Next thing we read about "what a nice guy he WAS". 

Regards

Tubes if found are $300 per.  No inventory anywhere.
what if manuf discontinues making special tubes in a few years.  Resale value of preamp is low. 

@emergingsoul please cut to the chase and tell all who's the manufacturer and what tube.