Not a bad idea. The trans will get more cooling than it does now, and so will the power steering. It's a nice, compact idea.
Trans coolers aren't expensive anyway. Most of us don't tow, so even a small to medium sized trans cooler is more than adequate. I have a Haden medium sized cooler (from Pep Boys) for the trans, and also use a ZJ trans cooler for the power steering. The PS cooler makes a big difference......no more screeching when working the crap out of it in the rocks.