because dropping one means you cared enough to send the very best (like the British SAS troops), or at least the most powerful non-nuclear weapon we have.

A 30,000 penetrating bomb would have to be carefully designed so a bomber could carry it. There are substancial size and center of gravity issues. There's also the problem of loading the thing.

If you want to drop it using a bomber, it'd have to be one with a huge bomb bay like the BUFF or a B-1. You'd have to figure out how you're going to lift it into the bomb bay. This thing is far heavier than any existing bomb, nuclear or conventional, so it'd need either a new bomb hoist or multiple existing hoists. There's also the question about how to configure the bomb releases. According to the FAS website, there were some monster bombs weighing over 15 tons produced back in the 1950s like the

Mark 17 but those were built in small numbers and didn't stay in the inventory very long. I don't know if they would even fit into a BUFF bomb bay.

On the other hand, if you're going to drop it from a transport plane like they do with the daisy cutter, you'll have to find a way to integrate the guidance system into the plane's navigation system. About the heaviest load that I've ever heard dropped from a C-130 or C-17 was the Sheridan tank that weighted about 17 tons, big enough for a Hallmark.