Not sure if you alreay knew this, but as an aside, there are a couple of ways to pin with shiho nage. One way -- which you see in Moreiteru Doshu's book -- is to hang onto uke's hand and follow him (or her) all the way down. This is trickier than it sounds, because for uke's safety, you have to drop quickly enough so his/her hand hits the mat before the rest of the body. If the body hits first, the unwinding of the arm could lead to inujury.

Due to flexibility issues, I can't drop quickly enough to get the hand on the mat first, but I have been on the business end of it when done correctly -- it's an intresting feeling of being controled all the way down.

Of course, the foregoing is from the standard standing reference points, but you can adapt it.

The joint locks -- ikkyo, nikkyo, and sankyo -- can also be used as throws. Sankyo nage can be pretty insane. But this shouldn't be a surprise because shiho nage is also based on a joint lock.

If you already knew all that, mea culpa. If not, thought you'd find it interesting.

Just my 2p.