I wrote this tutorial awhile back on writing nonstandard transactions. I have done all sorts of weird ones.

http://pastedown.ctrl-c.us/#_kbv9v7Bt2tAXE4y_XJjerp3HYE.markdown

I created this transaction and it is in fact unspendable due to the fact the alt stack does not persist from the scriptSig to the scriptPubKey. I'm glad it sparked some discussion though.