Don't know why you're all so convinced there are no tyres left in the correct SW20 profile for 16" rims. There's these for starters, which are rated really highly:
http://www.yokohama.com.au/Tyres/ADVAN-Neova-AD08.aspx You can also get Toyo T1-R's in the right sizes if you know where to look. That's what I run and I've always been very happy with them.
There are other options beyond these too.
(hint: Demon Tweeks is your friend – and they get them to you even faster than local suppliers can get tyres in)