You could look at race car shops, but they probably won't be chrome. The narrow race springs are 1.9" ID. On my CB350, the springs are 2" OD. So unless you can find the narrower spring, you might have to make a new perch. It would be hard mind you.
Alternatively, you could always chop a link off the spring. However, BEFORE you do this, you'll have to evaluate you wife's weight and the end-result spring rate. There are websites that show you the math for spring rate and the result of chopping a single link off.
I tend to be over analytical. If I shot from my gut, I'd probably wind the preload down as much as possible and chop off 1/2" of each spring--assuming the rider will be under 150 LBS or so.
--Chris