When I worked on my last proposal, I did also consider the UTH/DUTH solution that Steven Allan posted. I quickly discarded it, because it seems inconvenient as long as politicians worldwide can't agree on common dates of switching between summer and winter time. Any hour-offset change between TI and local civilian time should best coincide with the end of summer time, to minimize the number of jumps in civilian time zones. But as (at present and for the foreseeable future) summer time (or "daylight savings time", hey we can't even agree on a common name in English!) ends at different dates, it is not feasible to change UTH at the same date all over the world.
Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__