wheezy, grub2, hidden menu, shift-key to display menu

[Zenaan Harkness <zen@freedbms.net>]

I'm on a Lenovo Thinkpad X220 laptop.

$ uname -v
#1 SMP Debian 3.2.32-1

$ grub-mkconfig --version
grub-mkconfig (GRUB) 1.99-23

$ cat /etc/debian_version
wheezy/sid

$ sudo update-grub
Generating grub.cfg ...
Found background image: /usr/share/images/desktop-base/desktop-grub.png
Found linux image: /boot/vmlinuz-3.2.0-4-amd64
Found initrd image: /boot/initrd.img-3.2.0-4-amd64
Found linux image: /boot/vmlinuz-3.2.0-3-amd64
Found initrd image: /boot/initrd.img-3.2.0-3-amd64
Found Windows 7 (loader) on /dev/sda1
Found Windows 7 (loader) on /dev/sda2
done

Now, I searched the d-u archives, so sorry if this has been covered,
but I couldn't find it. I've also been googling and reading various
websites, trying various /etc/default/grub combinations, reading
grub-mkconfig man/info, but to no avail so far.

What I want to achieve:
A hidden grub menu, with or without a "press key for menu" timeout/countdown;
if I am holding down SHIFT or some other key on boot, I want the grub
menu to appear, but not otherwise.

Is this possible?

If so, how to?

TIA
Zenaan