I disagree with Rich. I run a frame constructed of 1.5"x8" mahogany planks for the side rails, and unistrut crossbars. The towers are a pyramid-shaped steel. Though I didn't weld them myself, I think they would be fairly easy to fab if you have the tools.
Steel Oarlock Stands
Mine are powdercoated, or enameled black, rather than the unfinished metal. I also think mine point the thole pin closer to plumb- not so far angled out, but it's kinda hard to tell from the photo on that link.
Sharp metal is a concern, but ground and finished properly shouldn't pose any threat greater than, say, drybox corners. I'm also very partial toward the wood side-rails. They're easy to walk on safely, strong, can set my beer on them through decent sized rapids, and easy to strap ammo boxes to where they won't touch the tubes.
The 2" tubular aluminium frames, that are so en vogue, I find dangerous ankle-breakers to try to walk on. Plus, the little allen set screws that hold many of the fittings together tend to wear grooves in the tubing, leading pieces to fall apart at generally unfortunate times. It's also not uncommon to see tubes that don't fit in the fittings anymore because somebody's cranked on the set screw a little too hard and dented the tube out of round.
Fish- I'll try to get a pic of my frame posted, or maybe a link. I think you'll be able to build something that will work well for you.