What do you mean by 'minimal'? If you're talking about wine and flash, there are 32 bit builds available to be installed in 64 bit.. But that's the way it has always been.
For the record Arch is one of the only distributions with sensible multiilib support. Most of the bigger ones require purity and force you to install a chroot if you want to run 32-bit applications. Fedora is multilib by default but it sucks because it always installs 32 and 64 bit versions of everything by default instead of reasoning that you'd be OK to use 64-bit most of the time by default.
I recently switched from 32bit Arch to 64bit and it works great so far, multilib included.