Moving Tablespaces

Hi!

Looking at the "create tablespace " command in the docs, I was wondering
how feasible it is to move a database/tablespace to another
server/instance of PostgreSQL.

Issue: moving databases using pg_dump and pg_restore is more
time-consuming than desired, requiring the db to be unavailable for a
while, which we want to avoid. Also, we want to minimize manual
processes that are more tedious and error-prone. I am looking for a
low-maintenance solution, thinking tablespaces holds the answer. If not,
is there a better approach?

Background: We have lots of databases with the same table structure,
with 1 database per client account on the server. I can setup the client
database tables to be built within a client tablespace.

   create tablespace ts01 owner acctname location '/path/to/tspace';
   create database db01 tablespace ts01;
   create table tb01 (...) tablespace ts01;

Question: if database created with tablespace, i don't need to specify
on create table, correct? Or good form to do it regardless (it makes the
DDL less generic).

Now, when one database outgrows the server and I wish to move it to
another server, can i simply copy the tablespace /path/ to the new
server? I assume the same PG version must be running on each server.

Will we have problems with the catalog tables? Would we still need to
dump/restore without data to copy over the catalog information and table
structures?

Thanks,
Allen