Velocity makes 406 rims without machined sidewalls, I used the non-MSW Aeroheat rims on my disc brake mini velo build but I had to order them direct from Velocity.

http://store.velocityusa.com/p/aeroh...x_20-406?pp=12

Or they offer the wider cliffhanger rim in non machined sidewall

http://store.velocityusa.com/p/cliff...f-hanger?pp=12

Its funny but the A23 is the only 451 rim they offer now but they don't have that one in non-MSW in any size sadly. I hope this helps