Hello Karl.

> No a ULN2804 is an Octal Darlington Driver array with an output (max)
> voltage of 50V @ 500mA.

  I think you mean "*Yes* a ULN2804 is an Octal Darlington Driver array
...

>  By tying two outputs together you get 1 Amp.

  I guessed this is what you were doing.  I had a good look around the
various permutations of these parts on the Web recently.  I think there
are some parts with 1A capability already, though you may run into
problems with total package current draw.

  I presume you are aware of the T-I TPIC6595 which integrates the shift
register and the current driver.  It is only rated 250mA continuous, but
I suspect there's a beefier version somewhere, possibly with 1A
capability.
--
  Cheers,
        Paul B.