It all comes down to supply and demand. You can only suck as much power as the feed into the
dimmer can handle.
So, if you want to load up more lights, you need to get a dimmer that either has a higher single phase feed, or go to a multiple phase feed. The small 4 pac dimmer I referred to in my initial post can
go up to 3200W, if I plug it into a 15A feed, rather than the standard 2400W / 10A feed (Remember that I am in Australia and our power is 240V).
The dimmer you are talking about is designed so that it can be used from a standard
receptacle (if I understand enough about your power in the US)
Somebody please correct me if I am incorrect on this.