Flimzy's answer didn't work for me, and I did not feel like spending hours decrypting and re-encrypting Windows to try stefan.at.wpf's suggestion.
Out of desperation, I tried fiddling around in the Grub command line, gave up and typed exit
to go do something else, and was presented with the TrueCrypt bootloader.
I was stunned.
I edited my /etc/grub.d/40_custom file to read
menuentry "Windows 7" {
exit
}
And it totally works.
Obviously YMMV, but here's my set up: TrueCrypt-encrypted-Windows owning the entirety of one disk, and Linux and Grub 2.02~beta2-29ubuntu0.1 owning the entirety of another disk. My Dell BIOS is set to boot from USB, then CD, then the Linux disk, then finally the Windows disk. I'm not sure how or why this works, but I'm happy it does.