In the interests of looking for ways to improve on ideas, here's a suggestion (although it is untested and might not necessarily work)...

Why not dispense with the bulky and heavy lockring tool altogether, and use Steve0000's piece of flat steel bent at the end, but sized to fit the width of a lockring and a notch cut in for the axle?

I know that it would require the lockring to be cinched down not-too-tightly, and the tool might need to be of heat-treated steel to get the strength in the prongs.

Or what about a tool similar to a pin-wrench as used to adjust bearing preload old-style bottom brackets?

It does seem to me to be a logical progression in keeping things light and simple, and reducing the number of tools required.

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The one biggie that relates to this (and seeing BBs were mentioned) is coping with servicing of the BB on tour. While sealed bearings have made things much better in this regard, and Hollowtech II makes getting cranks on and off much easier, there are still the issues of removing the bearings. With the old cartridge bearings (eg, Shimano UN54) the same tool could be used for them as for the cassette lockring and even freewheel cassettes.

Anyone have a good improvised method of removing outboard bearings on Hollowtech IIs? Or are people confident enough in them to not worry about having to remove them?