Hmm. I've had this thought for a while, just sat down to see if I could noodle it out in the GIMP... but unfortunately, my brain's not into working with beziers or masks just to create a smooth circle.
So, here's the idea: A smooth circle, of appropriate (thicker than the thin strokes of the A, thinner than the wide strokes) width, opening around the 2 o'clock position to accept the left leg of the 'A' in the now-current 'Amiga' typeface - or if that's a problem, the face it was derived from. The circle - representing the O - should be perfectly round, with a hint of feathering or antialias, the edges of the 'opening' curved off; the A should be sharp, possibly italicized, with the leg in the O clipped to fit the curve with some whitespace, as if disappearing behind the circle. The whole thing should fit on the same.. baseline?, which would look professional, and make it easy to apply to devices, letterhead, what have you. (If it looks like crap, then the 'O' should be dropped a bit, suggesting that the 'A' is rising from it.)
The open circle would represent the 'openness,' and the A the 'Amiganess.' Simple, tactful, hopefully not too trademark-infringing... and if it is, then "OpenAmiga" itself has the same problem, let alone the logo. For uses where color is available, the circle could be black, and the A red, or vice versa (unless you guys want to pick different 'team colors,' as well)... It's hard to guess which'd look better without a decent paint app to try it in.
So, like I say, anyone with skills who wants to borrow the thought, feel free. I'm all for scene efforts *looking* professional, whether or not I think they'll get anywhere.