I would be very careful about taking that deduction--home offices are the number one cause of IRS audits. (Not that you shouldn't take it if it's deemed proper by your tax advisor.)
If you wife can survive being trapped in the house, a home day care business can be amazingly profitable. I have a family member who makes $60-$80k easily plus the tax benefits. The tax benefits are really amazing since you can deduct almost all household improvements. The only downside is the tedium.