Recommendation for distributed IO

[wdoe999@xxxxxxxxx]

Hi - I'm looking for recommendations for inexpensive distributed IO
boards for home automation.
I'd like to monitor and control a few points around the house.  I'm
thinking of remote IO boards that talk serially to a central control
board (or maybe just a central linux box).  I've seen a few IO boards
here and there, with not too bad prices (around $50 US).  However,
they tend to have a lot of IO per board.  Is there something out there
that is even smaller and cheaper?  Let's say 1 to 4 IO points per
board, connected in a daisy chain.  Thanks.