Hi,
I'm not sure about Singapore....but if you are willing to drive
over to Malaysia, you'll find that their range of car locks is much
wider than here. That day, I was at Jaya Jusco (Skudai, Johor) and
saw many types. I'm not sure about the particular type you want
though.....but there are similar types (T-shape, etc).
I can't remember the prices, but I remember that they were quite
reasonable (most below S$100). I mean even if you have to spend
S$100 to protect your multi-thousand dollars car, I think its worth
it.
Er...I don't think its so easy to cut through the steering wheel.
The steering wheel, pedals and seat belt hooks (nader bolts) are
the hardest parts of a car. While it is not impossible to cut
through them, it would take an experienced person with a
specialised hydraulic cutting tool (which need generator sets to
work them)....and a considerably long time too.
Sometimes, simple things can also help to avoid car theft. Like if
your car is front-wheel drive, then park facing in and turn the
steering wheel a bit before locking it (to prevent towing). Use two
locks instead of one (to discourage any thieves). I've even ever
pulled out one high-tension cable before (the ones attached to the
spark plugs 
).
Of course, I agree with you that nothing is 100% fullproof....but
if after taking all possible precautions and we still suffer from
bad luck.....then its fated lah.
The more common crime nowadays is to have your windows broken and
your things inside stolen (eg. cash card, stereo, coins,
etc.).