Oh also, if some secondary operations are acceptable, and it's not so much the one-sided-ness as the low profile, you might consider countersinking the holes, and using cone screws. Works very well even in sheet metal, though you have to be more and more careful with just the right countersink depth and angle, and screw dimensions as the panel thickness goes down, obviously.
Secondary, merely because, if you ask the PCB fab to do it themselves, it's probably going to be a pricey custom operation for prototyping, and I'm assuming this is a few-off case by default. But you would of course want them to do it in production, and the cost will be reasonable then.
It will be difficult to impossible to get any kind of connection to the countersink itself, but a pad on the facing/mating side can still make a connection.
Or the countersink is made early in fab, before plating, and becomes a plated pocket, and you could get vias in and around it as well (drill small holes, then the large hole, then the countersink). (Done carefully, you could even solder in a cone-head screw as a threaded stud; you'd probably want to use solder paste, and a jig to hold it perfectly perpendicular.) This is generally even more expensive, but again might be a production option. Probably the solder nuts or other bracketry would be preferable at this point.
Oh speaking of bracketry; you could just do something like, get a slab of brass, machined, formed or cut with whatever holes or threads you want, and make an enormous lap joint soldering it to the PCB, spreading the load out over as much area as you can afford. This is a good way to get tabs, flanges, etc. onto a board, though do be careful about bending stresses, as for example a simple L-bracket sees exponentially more stress right under the bend, right into the solder fillet, whereas a reinforced (say the bend is embossed to put a stiffening ridge into it) or gusseted or tee shaped joint spreads it out further through the base metal, sharing the load into the solder joint and laminate more evenly.
(Brass can easily be tin plated, the best case for soldering, but can also be wetted by itself, though at some difficulty compared to the ideal case; hence you might "butter it up" beforehand. Which can include acid fluxes if needed, and then wash it off before soldering to electronics.)
And the above mentions of glue and VHB tape, a more permanent solution obviously, but if once is all you need, they're quite good for this.
Tim
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