Possible to include a per miner transaction to prevent withholding and independent rebroadcast of a solved block? Update: This is a bad idea because it simply won't work, but it did help me understand what happens between a Miner and a Pool.

And if you missed it in the comments, read @Meni's PDF for a threat and profitability analysis of pools.  



Is it feasible for a pool operator to include a "signature transaction" sending a small amount of BTC from and to themselves... and then monitor the public block chain for these addresses if share withholding (and subsequent solo broadcast) is attempted?

In other words, if a pool has 10,000 workers, then generate 10,000 addresses.   Then create a transaction with an output corresponding with the worker address.  Of course this money won't go to the worker (unless the operator desires it), but it can be used as virtual stamp on the entire block.


Is this a viable strategy?  If so, what scope is best for this check: per miner, per x miners, or per pool?


(I think the per pool scope may be a good way to get a measurement on % of cheaters)
I think you may be confused about what block withholding means.

Pools already assign unique work to miners which credits the pool, not the miner. A miner cannot take the block reward for himself.

"Block withholding" means the miner submits shares normally, unless the share happens to be a block. Then he withholds it for either sabotage or lie-in-wait. Since block finding is random, no "marking" by the pool can help it determine if the miner found a block or not.