'89 66cm Cannondale 3.0, '92 22" Cannondale M2000, '92 JxL Cannondale R1000 Tandem, '86 Cannondale ST800 27" (68.5cm) Touring bike w/Superbe Pro components and Phil Wood hubs.
27" Rim Options (630 bsd/iso)
Classic and Vintage bikes almost necessarily means bikes designed for 27" (630) rims. While you can make 700c rims work fine with long reach brakes, or on bikes with cantilever posts, the point is that there is absolutely nothing wrong with the 27" rim standard. Which is to say that there is nothing inherently better or improved about the 700c rim.
A 27" rim is really a 630mm rim at the bead seat.
A 700c rim is really just a 622mm rim at the bead seat.
For large frames (mine are 68.5cm) you want the biggest rims you can get, even if they are just 4mm larger in radius (8mm in diameter) to keep from looking "off".
Well...Velocity may have added more rims to their 27" offerings.
Recap. Velocity offers the following rims in 27":
Dyad in 48h
(Also known as Aeroheat AT, Super stout touring/tandem duty rim, think Mavic Module 4 or Super Champion Model 58/59 w/o eyelets)
I'm a fan of the Twin Hollow myself. Arguably the strongest single-wall rim I've ever seen. I'd expect it to outperform in strength in comparison to any other single wall rim on the market - and some dual-walls to boot.