I purchased a pair of these RIRO cranks from here:
https://a.aliexpress.com/_EudctB2 cost me £119 delivered to UK.
Leese seem to have a pretty much identical option.
The cranks use a dub 29mm(28.99) spindle and the chainrings attach using the shimano direct mount standard, though unlike shimano who I believe use a lockring to attach the chainring, these cranks sandwich the chainring between the crank arm and a flange built in to the spindle.
I believe rotor uses a similar mechanism with their Aldhu cranks.
Unfortunately however, the spindle on mine appears to be undersized, and there is a tiny amount of play in the bottom bracket. I’ve tried two different BB’s with the same result. The spindle is measuring in at 28.92/28.93. So, I’m currently processing a refund. I’d rather the seller would just send a new spindle but that doesn’t seem possible.
A pity as the cranks otherwise seem good, look good (imho) and are very lightweight. 571g (165mm cranks) including spacers and preload ring.