I'm looking for an example Bitcoin Block that would have a Namecoin merged-mined Tx in it.
Can anyone direct me to a block that has such a hash?
It won't exist. Merged mining only shows up in the auxiliary blockchain (Namecoin), not the parent blockchain (Bitcoin).
Basically, if you find a hash smaller than the target for both, then you submit the block to the Bitcoin network as usual and the Namecoin network as well. If you find a hash smaller than the Namecoin target but larger than the Bitcoin target, then you submit to Namecoin only. Basically the Namecoin blockchain gets stuffed with some junk from the Bitcoin blockchain.