Re: reuse tablespace from crashed PSQL instance

There is nothing in relation data files that prevent you to do it (no headers etc in files) except xmin and xmax info from tuple %). 

So the short answer is yes you can do it but may be you will not see any data from it if for example current txid is less than xmin's from data files.

PS There is no transportable tablespaces as they are in Oracle. So you can only try it  at home ;)