From the developer's list:
Dries >> So, if I understand correctly, you suggest that introducing more types (i.e. float, integer) and corresponding validation routines in core would be the first step. This makes sense to me, and shouldn't be too hard. Is anyone working on this -- or willing to work on this?
Adrian >>I think perhaps we should look at more semantic data types than just float and integer.
A good example of this would be a title type. Which defaults to textfield, and automatically does the plaintext validation and formatting on output.
The same with 'markup' or similar, which automatically expands to a widget that has format selectors.
'id' field type could also be useful.
Especially when integrated into a query builder, and even if only for constructing crud functions such as drupal_load('objecttype', 'id1', 'id2');