There are options in the Table toolbar for editing cell and row styles. In both, you have to option to apply your changes to more or all of the table. You can play with it here on Jivespace, and I'm including screenshots of the option sets.
Table menu in the rich text editor:
The 3rd button opens table row properties:
The 4th button opens table cell properties:
Hope this helps!
Yes, but this isn't a table style per se.
In Plone there is are some basic table styles available, allowing you to choose a particular kind of table style when the table is created. There is also a feature to create styles that can be applied to rows (such as the shaded style). This is the kind of functionality that I think is being proposed.