MOTM

Personally I would always go for two smaller power supplies than one big
one. I know size may be an issue, but there are advantages to a
distributed system of smaller supplies.

Firstly, if your power supply dies, there is less chance of every module
being affected. This is unlikely with a Power One, but things do go
wrong.

Secondly, a higher rated supply, say 3A, will be quite happy to drive 3A
into your whole system or just one module. So if you have one faulty
module it will quite happily chuck 3A into it and possibly burn something
out.

Thirdly, you can more likely ensure that the +15V and -15V lines stay at
that level if the power busses are shorter. Which they would be with a
smaller system of multiple busses each driven from their own supply,
compared to one large distributed buss driven from one supply. Also any
noisy modules that you may have can get their own supply leaving the
audio pathway to have a nice clean supply for itself.

Fourthly, Power One supplies do latch up with less than their maximum
rated load. This is a flaw with their design whereby one supply line
powers up before the first so the other one switches off. I have a sneaky
feeling that using two smaller supplies will actually get you more module
count than one bigger one.

In a nutshell it is probably better to use two MOTM supplies not one 
bigger one.

Tony