[Gustomaximus]

We do this in Australia (($18,200). It largely works well. The downside is people can use others tax free threshold. E.g. If someone is working and is married to housewife plus has a couple kids at uni, if they have a business or assets in trust they can distribute $20k to each person so now they have $80k effectively tax free.

I'm not sure the scale of this being taken advantage off though but it's well know benifit if you situation allows.

[chrismcb]

This should not be a problem. Basically you are saying each person gets 20k tax free. If one person is earning and supporting the other then yeah they should get 40k tax free. But if they are both working they will still only get 40k tax free.