Locking board-to-board connector?

[rexxar]

I decided that I need to stick a daughter board on this project, and now I need to find a connector for it. However, the board is going to experience a lot of physical shock, so I'm concerned that a regular connector would come loose. Obviously the best thing would be to directly solder the boards together, but it's an optional module, so I want the end-user to be able to purchase it separately and install it themselves, so I need a connector.

So, I wonder if there's some sort of locking board-to-board connector I could get that would withstand physical shock? Or maybe I could use some sort of locking standoff, but I'm very limited on space, so I'm not if that's a viable option...

Any ideas?

[mariush]

jst hvq
jst jl
jst mq
jst jdf

etc

Catalogue here: http://www.jst-mfg.com/product/pageview/connector_e/pageview.html#page_num=312

Alternatively, there are standoffs/spacers out there, you could just make a hole on each board, screw the standoff on the main pcb and supply the daughter board with a screw to lock the board completely.
See for example: http://uk.farnell.com/standoffs   M3 screws are super cheap (the ones used on optical drives, floppy drives, ssd drives etc), standoffs with m3 screw thread are super cheap in quantity.
It would add some extra work on installing that standoff in the first place.

[SL4P]

... or those nylon snap-fit standoffs?