Incremental clustering?

The docs say:

"Clustering is a one-time operation: when the table is subsequently updated,
the changes are not clustered. That is, no attempt is made to store new or
updated rows according to their index order. If one wishes, one can
periodically recluster by issuing the command again."

and

"During the cluster operation, a temporary copy of the table is created that
contains the table data in the index order. Temporary copies of each index
on the table are created as well. Therefore, you need free space on disk at
least equal to the sum of the table size and the index sizes."

I don't relish totally locking and making a temporary copy of my biggest
table, but that's exactly the table that seems to need clustering the most.
Will subsequent cluster command also make a complete copy? Some form of
"incremental clustering" would be nice...

-John