Hi All,
Have just passed 5000km+ with the belt/pulley system....the setup was fitted when the bike had 40053km on the ODO, it now has 45065km, everything is still working fine and no issues to speak of, belt is holding up well with no signs of excessive wear or cracking/splitting. Luckily I've had no stone damage either. I've been riding it normally as I did when the chain/sprockets were fitted, most of my riding is a daily ~50km each way commute to work and back, I also do ~200km Saturday/weekend rides with local riding friends, weather permitting.
I haven't noticed any change in performance or associated issues. It's also a pleasure to not have to clean, lube & adjust the chain every 500km or so and clean all the chain lube crap etc of the back wheel/swingarm and back of the bike every time I wash it...now it's just a quick snow-foam all over, wipe over with a sponge and hose off, job done.

I have adjusted the belt tension once since fitting, I asked one of the guys on the BMW F800GT forum what tension they use and I have adjusted mine to be the same, I was running mine a little "tighter" than his recomended tension but TBH I haven't noticed any real difference. The difference was only a kg or so per 10mm of belt travel.
I'm planning on making another belt/pulley kit in the not too distant future, it will be essentially the same setup but hopefully be a lot more "precise" than the "hand made" setup I have on at the moment, possibly a month or two maybe...just need to get some parts ordered, new rear pulley, shoulder bolts... and make the front pulley, spacers etc....will get a new belt too. I still have a new spare belt in the shed just in case. I'll take some precise measurements of the front pulley when it's done and see about getting one CNC made locally....this will make it so much easier...making the front pulley at present is very labor intensive and time consuming using the equipment I currently have at my disposal.
I'll fit the new system to my bike and I'm thinking of possibly asking one of the nearby Aussie Experia owners if he would allow me to fit the old setup to his bike and run the system to see what he thinks and if it's a viable alternative to chain & sprockets. Time will tell.
So far so good guys.
Smithy.