IEEE 754-2008 decimal numbers

Hi

Has anyone done any work on IEEE 754-2008 decimal types for PostgreSQL?

I couldn't find anything, so I was thinking it might be a fun exercise
for learning about extending PostgreSQL with user defined types.  My
first goal is to be able to store decimal numbers with a smaller disk
footprint than NUMERIC.  I was thinking I would start out by defining
types DECIMAL32 and DECIMAL64 and some casts between those types and
NUMERIC.  (A more ambitious project for later would be defining
arithmetic operators etc using compiler/hardware support).

Thanks
Thomas