Scully,
This is the stuff I've bought from Marmitek (via
www.intellihome.be (or www.letsautomate.com if
you are in the UK):

1x IH3080/IR7243: Mini-Controller (picks up IR
from iPronto and changes it to Marmitek X-10 signals).
1x IH3010: Computer Interface
6x IH4020A/LW11 Walldimmers
12x IH1210/LM12: Plug-In Lampmodule + dim

All in use without an extender.
Succes,
Kees