I've been looking at this for a couple of years now - to little avail. I've tried every screen available and am now going about making my own fairing and screen.
Like you i'm shorter in stature so we can't get our head up into the clean air. Even the Britannia Mirage doesn't work as the sides cause turbulence.
Also going against us is the headlight unit - not at all aerodynamic. And i have suspicions about the beak - BMW have now copied the Multistrada 1200 beak that is smaller and has faux intakes on it which i'd suggest would reduce the pressure on the headlight unit and subsequent noisy air travelling backwards.
Looking at the big sport tourers (I'm thinking FJR1300 / ST1300 / Concours 14 http://www.youtube.com/watch?v=CnkpM-OsyZg ) they all have smooth, aerodynamic fronts and floating adjustable screens. Admittedly these screens are sized similarly to the riders torsos which i think would look a little silly on bikes like ours... The closest thing available to these is the Madstad however it wobbles a lot and months of trial, error and deafness i couldn't find a quiet spot.
So my solution is to use a base similar to the Madstad ( http://www.madstad.com/s.nl/sc.7/category.1118/.f but smoother, less wide and better fitted the bike) then a large-ish mildly formed screen (i may even find a secondhand screen from one of the above sport tourers) will be posting results, hopefully before the summer touring starts!
In the meantime it may be worth trying to raise your seat (if you are comfortable with this) then getting a cheap screen that you can heat to mould and bend down. This will have the effect of all the turbulence being on your chest and your head in clean air. I've nearly got this working using the WRS screen and a cheap yoga mat cut into several pads to raise my seat height (it's currently being re-padded professionally so i'm hoping to dispense with the Blue Peter approach soon!)
Best,
S
Just to add my experience. After trying the std 800 screen, a Metal Mule and the MRA Vario with spoiler screens I tried an Isotta Screen (Same as the Wunderlich, but cheaper) and it's brilliant, I am really chuffed. I can ride at 80 with my visor up and wind noise is barely there. I am short though (5 foot 6 and a half
FYI - This is the screen i bought. http://www.ebay.co.uk/itm/130820030886?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
Really really happy. For sale shortly are my 3 other screens