So you will have OOTB 32 bit support (with security updates) until at least 12 months after Debian 8/Jessie is released (which should be a year or 2 away at least).
As Alon mentioned building 32 bit in 64 bit environment is possible so even beyond that hopefully TKLDev will be able to build 32 bit appliances...
AFAIK v13 will be last 32 bit release
So you will have OOTB 32 bit support (with security updates) until at least 12 months after Debian 8/Jessie is released (which should be a year or 2 away at least).
As Alon mentioned building 32 bit in 64 bit environment is possible so even beyond that hopefully TKLDev will be able to build 32 bit appliances...