Steen,
This is a very nice set of VIs. Thank you for posting. I'm one of the developers and current owner of the CVT library, so this is of special interest to me.
I really like the ability to dynamically create new registers by simply writing to them, which is a feature we've been planning on adding to CVT for some while. I also like how you handle dynamic and static names in the VI registers using two feedback nodes. I would like to borrow this idea for CVT to eliminate the need for dual dynamic and static name access VIs. With CVT we have not added a polymorphic wrapper, but of course you could eliminate the need for separate CVT VIs for each data type, as you have done.
One big difference I see is the low level read-write performance. One of our main use cases for CVT is LabVIEW RT on cRIO, which is a much slower processor than most LV programmers are used to from Windows. Doing a very quick comparison between VIRegister and the static access CVT VIs I see a 10x faster access speed for CVT. This is not surprising as when we designed CVT several years ago we benchmarked all the different possible implementations on cRIO and picked the fastest one we could find.
Currently the name lookup in CVT is very slow (linear search) as Mads has indicated and we plan on fixing that by using variant attributes to store the tag data and using its built in binary search.