Support for BigDecimal
Sometime this weekend, I expect to put a functor-based implementation of Validator into my incubator area. The impact on existing jdnc code is that most of NumberMetaData ends up gutted (the five implementations of RangeValidator all fall away), and NumberMetaData ends up working for all Number implementations that also implement Comparable (which is all of them in the JDK (some third party Numbers may not (but off the top of my head I don't know why they wouldn't))).
Whether y'all decide to adopt it, adapt it, or ignore it is one thing. I really want to stress, however, that I think it's terribly important that JDNC support BigDecimal in every area where numbers are associated with currency.
In shops I've worked in where code is reviewed, that is one of the bullet points that gets checked. When I've been involved in interviewing, it's one of the few filter questions that I have (depending on the position and environment, of course). I believe that you never want to put someone in the potential position of having to tell an accountant that some number represents 'approximately' a dime.