I don't think its useful. The amount of people who want a 3.2 emunand have got to be very small (probably just you and maybe a handful of others TBH). In those cases, users could just use modmii's emunand modifier to install a 3.2U system menu wad (and IOS30) overtop of an existing emunand, or create the nand from scratch using showmiiwads, or just exract their own personal 3.2 nand dump.
The main reason why I don't want to add support for it is because to keep things consistent I'd need to offer all the themes currently offered on 3.2 in wad form and csm form (thats 32 new files I'd need to support).
That being said, if you still want it by the time my exam is over (June) I'll reconsider the idea.