Does anyone have any experience of this modification?

http://rubberchickenracinggarage.com/bushings.html

The basic premise seems sound, i.e. a roller bearing is designed for rotation not oscillation, but is the OE arrangement really that much of a problem? I bought my paralever 100RS 16v just a week ago, so I don't have any personal experience yet.

When Paralevers were commonly in use as a current item in K Bikes, Oilheads and etc, I used to stock about twenty of those tiny sealed bearings at the shop...

There has been a lot of talk on other forums about the pros and cons of them.
Everything put there doesn't last well and rubberchickens gear seems to wear as much as others. The big problem is that a larger diameter bearing is needed but the room isn't there.
Those bearings are 32mm OD, if a 46mm bearing was used double the strength is obtained.
BMW just didn't get it right this time.

So should I conclude that the only reliable course of action is a regular strip and lube? It does rather negate the perceived maintenance advantages of shaft drive, but I supose that it is a price worth paying for my reinvigorated BMW habit. Thanks for the tips.

The bearings are sealed on both their sides so "maintenance is not required". Just check them every so often for wear which will be a noticeable side to side play when grasping the back wheel and swingarm and hoisting it to and fro, while the bike's on the centre stand. A small amount of play at the bearings will translate to something you can feel at hand there. I have seen where the large Allen bolt flange has almost siezed to the swingarm and requires replacement as well. They are under a lot of torque.

I think this bearing taking a whole heap of load is an issue but when you add up how many hundreds of thousands of Paralever-equippped bikes there are running round successfully for all these years - since the Airhead R100GS/PD! - it is not too big a deal. Change the final drive oil using a quality hypoid GL5 gear oil, then go for a long, enjoyable ride. There'll be never a chain & sprockets to adjust or clean or change ever again.