I think you'll find interest for a combined alternator and PS pump bracket, as I don't know of a production bracket or set of brackets to allow PS on a 235/261.

If you do make one I think you will run into belt slipping problems if you don't provide more belt wrap/contact on the pulleys.
I know I had a somewhat difficult time keeping my belts from slipping when I piggy backed the PS pump on my generator.
Like this: http://rides.webshots.com/photo/1484181889080251109UpSqhH
http://rides.webshots.com/photo/1484223987080251109mvGaMx
In that case the fan belt was as original with let's guess at 100 degrees of belt contact. With the added load of the PS pump also being driven by the fan belt on the generator pulley it liked to slip the fan belt if not kept tight and clean.

You might want to consider adding an idler pulley similar to what I did here:
http://rides.webshots.com/photo/2724272330080251109JbMOHu
I did it to keep the PS belt off the air compressor, but it also ads more belt contact to the pulleys, which is what you'll be after.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-