Sigh! Didn't really answer the exact question but solves my deeper issue of "run lion, run windows, keep both secure". Here is what I ended up doing,

• Moved my physical Windows 7 system as a VirtualBox machine inside Lion (details below)
• Deleted the Truecrypt'ed Windows 7 partition -> single, large Mac partition
• Turned on FileVault2 inside Lion

I get the same end result of having everything on the laptop encrypted but had to compromise on running Windows 7 a bit slower as a virtual machine instead of a physical machine.

Migrating Windows 7 physical -> Virtual machine:

• I used EaseUS backup software to make the backup to an external hard drive
• Booted into Lion, created an empty virtual machine
• Used EaseUS's "restore to dissimilar hardware" feature

http://www.todo-backup.com/backup-resource/universal-restore/restore-system-to-dissimilar-hardware.htm

It took time, but it was mostly unattended so wasn't that unproductive.

Also, I noticed that Windows 7 32 bit was running a lot faster (50% faster compiles in visual studio 2010) than Windows 7 64 bit. My laptop is a core2duo and a total of 4GB memory - I suspect memory is the bottleneck as the Win7 32bit machine requires a little less memory than it's 64bit counterpart.

Same thing happened to me on Windows 10. In my case the enable bitlocker process changed the type code on my OSX partition. To verify and fix on windows, use gdisk. http://sourceforge.net/projects/gptfdisk/

Verification

• Open Administrative Command Prompt and run gdisk64.exe (assuming x64).
• "0:" which is a special syntax to describe disks in windows. (I only have one harddrive and 0: is the first)
• "p" to print the partition table

Type device filename, or press <Enter> to exit: 0:
Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Command (? for help): p
Disk 0:: 977105060 sectors, 465.9 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): FDABFC64-BD61-4C2D-95CC-AB54D6A16DAA
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 977105026
Partitions will be aligned on 8-sector boundaries
Total free space is 4028 sectors (2.0 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1              40          409639   200.0 MiB   EF00  EFI System Partition
   2          409640       293378375   139.7 GiB   0700  Customer
   3       293378376       294647911   619.9 MiB   AF00  Recovery HD
   4       294649856       976392292   325.1 GiB   0700  Basic data partition
   5       976394240       977104895   347.0 MiB   2700

In my case partition #2 is my OSX installation. Note that Code is 0700 which is incorrect (gdisk describes 0700 as "Microsoft basic data"). If you see the same thing proceed with the fix, if not stop here. Also, double check that your MBR is protective and not hybrid.

The Fix

Command (? for help): t
Partition number (1-5): 2
Current type is 'Apple HFS/HFS+'
Hex code or GUID (L to show codes, Enter = 700): AF00
Changed type of partition to 'Apple HFS/HFS+'

Command (? for help): v

No problems found. 4028 free sectors (2.0 MiB) available in 4
segments, the largest of which is 1947 (973.5 KiB) in size.

Command (? for help): w

• "t" is the command to change a partition's type code
• "2" is my OSX partition index (use yours)
• "AF00" is the type code for Apple HFS/HFS+
• "v" verifies the disk
• "w" writes the table to disk and exits