Greg,
This is not new, unfortunately. I have encountered it myself, several times in the past. It's really, really frustrating to not get some sort of response. How much effort is involved to reply to you and say "Sorry...SOLD"? At least you would know and could put it behind you. People are strange and often inconsiderate.
All I can say is: don't give up. Just keep looking and sooner or later one will pop up and you can begin the process of adapting it.
This is not new, unfortunately. I have encountered it myself, several times in the past. It's really, really frustrating to not get some sort of response. How much effort is involved to reply to you and say "Sorry...SOLD"? At least you would know and could put it behind you. People are strange and often inconsiderate.
All I can say is: don't give up. Just keep looking and sooner or later one will pop up and you can begin the process of adapting it.