More flexible (and thus more useful) iron platforms

Iron platforms are currently too unflexible, as the size and height is fixed. For the price they cost there should be more flexibility:
-Let me build the pillar independant from the top plate
- Pillar can be built to an individual height, e.g. height 3-7.
- Several top plates to choose from, e.g. in dimensions 5x5, 6x4, 7x3. Placing a top plate one field off-centred should be allowed.
- Offer special versions of the pillar that either integrate stairs/ladders or a vertical power shaft