I used the Bootcamp Assistant and told it to remove the Windows 7 partition, etc.. I never got a confirmation screen or anything saying that it was complete, but I also got no error messages, so I assumed it must have been ok, but since having the issues I believe it crashed at some point in the middle of the process.
If I restart the Bootcamp Assistant now, it acts as if Bootcamp has never been there - it asks if I want to download the tools and/or install Windows 7.
I have solved my own problem. I was unable to resize the partition into the free space because it was encrypted with FileVault (and was thus a logical volume in a physical volume).
I turned off FileVault (that is, I unencrypted the drive, which took about 12 hrs or so), and after using Disk Utility to verify the disk, went into the Partition tab and expanded it right up. No sweat.
Time to re-encrypt the drive now...that should only take another 12-24 hrs... :-)