Hi Robert theres not much available for Visions in regards to bars or risers, inherently there is no simple answer to risers as the general design of the bars and bike make it difficult due to a lack of space.
There are a handful of after market bars available from the US, some of us are using the Arlen Ness Ape's that are available Chrome or Black
HDM are another option
Im aware of a guy that modified the bar mount to tilt the standard bars forward and up giving a 2' lift at the handles and little if any interference around the mount 'but' i have no idea how to find the link as it was a long time ago, from memory it was an angled bolt mount not that higher just tilted.
I have Arlen Ness Ape's on mine, i Love em buts it a major difference from just a small riser lift.
Burleigh Bars in Burleigh Heads QLD make beautiful custom bars.
They made me a really trick set of 1 3/4'' for my then CCT, I now have a Vision and considering getting a 1 3/4'' set with a little more pullback for the VV.
You can have a look at there web site for the type of work they do, beautiful bars...
these might do it ? . http://www.store.extremecreations.com.au/angled-billet-bar-risers
sorry I didn't realize they had a flat base . the same mob do custom risers as well - and there in Sydney .
they could whittle out a bit of billet for you ?