Unfortunately not, basically each orientation is a separate block id. We cannot add more block id's at the moment without doing some adjustments to the way how blocks are stored in the database. That wouldn't be too much work, but it requires a conversion of existing worlds (and we don't want to do that too frequently, since there is always a chance that something may go wrong^^). There are some other changes we want to do to the block/construction system, so it's our intention to do all at once
OOh, gotcha. I just assumed each block also had some rotation info bundled with it. I see the dilemma. And yes, database changes are not to be taken lightly.