Installing the 32 bit version of Sonar is completely free and it runs 32 bit plug-ins like a charm, and doesn't take much extra space alongside the 64 bit install.
Bridging, wrapping and other assorted hoop jumping who needs it?
It's not like you have to keep your 32 bit version updated with all your latest and greatest plug-ins to stay in sync with your 64 bit version if you don't relish the idea of keeping two versions in step with each other you don't have to.
But man if you have a real need to use your old 32 bit DX stuff or VST(i)'s that don't like being bridged it's the most perfect solution. The lengths people seem to go to in order to appear to stay as 64 bit purists seems bizarre to me, especially when if you think about it any advantage of running native 64 bit is lost as soon as you introduce anything 32 bit in the chain. What does x-ing out even mean?
Just run the stuff you need natively. Most decent installers these days just drop the appropiate version in both x86 and x64 folders anyway, so all you're doing is keeping the stuff you say you don't want to do without without giving yourself the headaches of trouble-shooting bridged and wrapped garbage.
Simple is good.