As an update that has been years in the making...
I am working on the rack kit again. The goal is to produce a 1RU kit that allows you to take your EX-800 or Poly-800 and put all of it into a 1RU enclosure. The idea behind this is that quite a lot of people are wanting to put their old keyboards into their studios but use a PC and or other composition tools and MIDI controllers etc and really don't need or want the synth's to take up much space. The EX-800 was a bit of a fail in that it takes up 5 or 6 RU's in a rack.
I will have more details soon but I've decided to just go with the original seven segment displays instead of an LCD. This makes it alot easier to make the kit useful to alot more people because you don't need to HAWK your Poly to use the 1RU kit. It also means that I can source a very cheap (but pretty good quality) 1RU enclosure.
More details once I get further along with the kit.
Cheers,
Mike