Sending regulars into Iran would be counter-productive from a propaganda viewpoint especially if they were caught i.e. remember the British sailors Iran detained.
Not necessarilly.
If the Iranians were holding any American soldiers, regardless of where in Iran they were siezed, the Bush Administration could just launch a "rescue" operation of a few brigades or so, along with the air strikes the Pentagon is planning. Maybe Bush could even don another flight suit for a photo-op carrier landing somewhere.
In fact, having some Americans held by the Iranians would likely be the dream-come-true for the NeoConservatives now in control of our government.
And, if some of them were killed, well that would be even more White House prayers answered as the US could "avenge" the atrocity.
Bush is going to get his third war, no matter what.