I just want to throw my experience in here and say that I think this is heavily dependent on your existing configuration. Overall, the Orbit enclosure worked pretty well for me, although it's not perfect. I had the opposite problem that you had regarding the conduit; my existing conduit lines up perfectly with the Orbit box and did not line up at all with any others.
The only issue I had is that, as you noted, the box isn't quite wide enough due to the power connector on the right side of the Iro. I just dremeled out a small bit, and the cable just sticks out of the side of the box. The hole is small enough that moisture getting into the enclosure isn't an issue.
The mounting holes, as you said, didn't perfectly line up either, but that was just a simple matter of quickly drilling a new hole. I ended up pretty much centering the IRO in the enclosure, which meant that I could use the existing bottom hole and drilled a new one for the top.
I'm curious how you're mounting the Iro's power supply in the enclosure that causes it to not fit. I have mine in there and it's not tight at all...plenty deep.
Anyway... I agree with you that we need more options, and something that REALLY fits the IRO and works with a variety of standard conduit configurations. But, the Orbit box certainly did a passable job for me.