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Browsing through ebay, just seeing what amazing deals I could get myself (turns out used stuff still seems to be going about 20% more than CRC sell it new) I came across an interesting design for an oval ring.
It's a 30t ring that bolts onto the inner bolts, and has a small amount of adjustment via a small plate on the rear of it. Firstly a 30t ring on the small position sounds quite weak, but the size of the plate they are using (and the single 3-4mm bolt) to hold it looks like it would break at the first hill!
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It is dished to keep the chainline ok, but I still imagine it would be a bit to far in for most setups.
Assume adjustment is to tweak the position of the oval.
The small bolt will be in shear so should be ok, plus I assume the compression action of the chainring bolts will also hold it in place.
May be a bit flexier than a ring using the 'normal' tabs and will leave them sticking out looking ugly and possibly getting in the way but I can't see why it wouldn't work in principle.
I have had half a bottle of Rioja though...