NoTubes has an exciting new 700c aluminum clincher road rim that weighs only 340g. The ZTR Alpha 340 700c road rim also uses NoTubes exclusive shorter rim bead. We will build a pair up as soon as we can order some rims - it looks like 28h and 32h are the first options on the way. I hope a 24h is available for lightweight front wheels soon.
Update: Originally rumors on the interweb had these rims as wide as 22-24mm, which is wider than even the HED Ardennes or the Velocity A23 rims. However, according to final specs and report on cyclingnews.com it appears that they are 20mm wide rims, which while closer in width to the Shimano tubeless wheels, they are still slightly narrower. This means they should still be good for a lightweight build.