Rather than the longer solution proposed by Dahon/Tern to hold a bag in the front, I'd rather use a Brompton-like baggage block because 1) it can hold more (7kg vs. 10kg) and 2) the bag doesn't move sideways as much.
What I'd like are solutions 3. At worst, I can always hang a bag from the head/steering tube using solution 2, but it makes steering harder.
Does someone know why Klickfix et al. don't make similar luggage blocks for Dahon/Tern?