Great minds think alike.
I'm gettting the MMS FC once I install the english pack also.
I also tried pushing MMS.apk from older ROMs and doing a permission fix.
About to hop on motorcycle and head to work. Will send logcat later on.
I have no problem on my Nexus S with language pack C, but the problem still persists on the Nexus One. I wiped data as well as the caches, and I even tried it using the Mms.apk from the NS 1c build (with a wipe in between), and still no go.