GTSBoy is spot on regarding Whiteline. I think Noltec do one as well.
I can supply this if you need one. http://www.whiteline.com.au/product_detail4.php?part_number=W82918 My price will be less than the listed price.
You can also buy an adjustable turnbuckle for around $80 (right hand thread on one end left hand thread on the other, with weld nuts, and lock nuts) which will allow you to modify a standard bar to become adjustable. I've done a couple of these in the past, and they work fine.
The main issue with cutting and shutting to make a shorter, fixed length bar, is you will have to purchase bushes; as the heat of welding next to the eyelet will melt the OEM rubber. I definitely wouldn't recommend cutting the centre of the bar and re-welding; even if you plan to drill the centre, pin and plug weld the bar.
If you can't fabricate it yourself, it will likely cost you more to modify than it's worth due to the bar being solid and needing additional material to modify correctly.
PM if you'd like any assistance.
Cheers, Dale.