They could backorder them like everyone else does. Advertise a product and price. Accept orders at that price for existing stock and scheduled deliveries. And repeat that process as more become available.
As an optimization, allow a fixed-sized queue of "pre-orders" at the same price. Though you have to be careful with this because you're selling things you aren't guaranteed to get. Amazon can cover the losses from mistakes here, small vendors can't.
It is obvious that demand was way more than supply. When demand is too high, you raise prices to decrease demand to match with your supply. When you increase supply you can lower prices to have demand match it.
In the long run they want to make it so everyone can have one for cheap, but really they don't have the infrastructure to do that. By selling at a higher price they can use the extra money to build out that infrastructure and then lower prices.
So should they have announced higher prices recently and had to face all the "knew they couldn't do it at the prices they promised, was all nonsense!" opinions? Or should they have never announced their real prices, and not got so much good press?
The other option would be directly selling them themselves, instead of being at the mercy of a few existing retailers.
I'm not sure that would go smoother, but at least you wouldn't have to go to each retailer and sign up for their lists or having to check their sites which one will get a new batch first.
(EDIT: I'm not saying I would think that's a good idea, but I think that's what the GP meant)
In the future you will be able to buy directly form the few existing retailers.
The only reason that you can't now is because they sold all their product. Both RS and Farnell are pretty large distributors (worldwide, not just UK) and should be able to easily meet demand. Only problem is confusion about selling to individuals not businesses, but that'll get solved.
EDIT: The foundation is a non-profit charity, where everyone involved has other jobs. That sounds sub-optimal for receiving orders, processing them, shipping them, and handling returns. It's much better that they've outsourced that to companies who are in business to sell stuff.
Well, the way it's done now, once evertyhing gets rolling there'll be enough Pi's for everyone. I can appreciate using experienced distributors instead of potentially facing much larger problems and delays. I agree it's not the smoothest of launches but from what I hear it's not much easier to get your hands on a new Apple device..
The speed benefit of not having to take a guess on one of two distributors would be more than wiped out by the delays caused by rPi having to do it all themselves, and would likely make it harder for them to meet their price targets.
And regardless, even if you ignore the downsides, at the very best all it would do is make the way a little easier, it doesn't solve the op's problem of having to wait before buying.
I would have preferred they sold directly. It is not so much the logistics, but that they have lost control. And lets not pretend that these companies are doing it for love-- they are taking money that could have gone to the charity.
On the launch they had no idea one of the retailers was only going to take a statement of interest. I'm still not sure what's going on at RS.
The servers were woefully under-prepared-- if the Pi folks were running it they could have thrown it up on AWS for an hour and then thrown up a static 'sold out' page. No faffing around, no attempting to register on a server that was being DDOSed.
This announcement shows they don't seem to have control of their pricing either. It's not the end of the world, but this seems like something they should be in control of.
As for the logistics side, I don't actually see why they couldn't have handled it themselves. They already had a payment processor set up for badge sales. I'm pretty sure 10,000 rPi's, 10,000 padded envelopes, and a printer could easily fit in almost any room. So all they would have to do is sort things out with a shipping agent, and hire a few people to pack them. IIRC, Amazon offer this service (send them boxes of something and they'll distribute it) so they could have even avoided this and still retained more control.
Would you rather they not let anyone buy them until they had more than enough to sell to absolutely everyone who might want one?
Or is there a third option that they should have taken?