I have updated the draft, to appear soon.

Changes done:

   - There are now two reference implementations, one
     based on vectors and the other on closures.

   - The reference implementation has been simplified a lot
     (although it is still complex syntax-rulesery, I know).

   - I have removed the variants label and (label) for the
     field specs as Alex asked, but I have kept immutable
     fields - sorry Alex.

   - changed record-update. to record-update*

   - rearranged order of record and type for the updates.

   - renamed record-extend to record-compose.  Record-compose
     does not require the export type to be a subtype of the
     import types any longer.  See example.

Regards
Andre