Views single table

This should some day be a display plugin for Views
(or even better, a proof of concept on how to patch the original table plugin)

It renders like the standard table plugin, except for the case when grouping is used, where this will render a single table with multiple tbody parts, as opposed to an independent table per each row of the grouping field.

I am not really a coder and not sure if/when i will really do this, but my starting-point is in this issue here: https://drupal.org/node/1365112

Another module around grouping and tables in Views is Views Gouped Table.