yeah, i meant a small company compared to intel...
taken from hexus.net:
"Demand is a strange animal. Sometimes both Intel and AMD have to fulfill demand for various grade of CPU by using certain wafers, and like any cost-conscious business, AMD try to minimise production costs by employing the minimum number of fabrication lines as is possible. Therefore it's quite possible to earmark a particularly pure wafer, initially destined for XP2400+ speeds, to lower speeds. Market demand dictates all."
so there you go 
Indeed. Good quote, but I'd still need confirmation before I'd actually believe it
They just suggest the possibility.
A few people have popped off the heatsink in pre-made (dell, hp and compac, IIRC) systems, and the printed speed on the CPU was higher than the rate they thought they bought! And sure enough, when they overclocked it, the number printed on the chip was a little under how high they could overclock it to. This is the extreme end, propably where the CPUs were already put together, but a huge order from one of the huge customers of a lot of the slower cpus was not able to be met at the last moment because of a delay or something; so the only chips at hand, the faster chips, had to take the place.
I read this off
http://www.hardocp.com/ and
http://aceshardware.com/ a long time ago IIRC. Probably not enough proof for you, but thought I'd mention it.

I think the demand grew for the 1700+ because it was such an "overclocking beast" (as I've seen it called on the Anandtech Forums) and not that it became the overclocking beast because of the demand.
Of course: overclockers make only a small bit of the demand; most is from OEM customers rather than BYO people. Sort of like us BYOAC people are to game controller manufacturers.

I'd also be curious to see pricing on the actual manufacturing level for a CPU. I mean, now that I think about it, other than R&D, wouldn't all CPUs cost approximately the same?
Manufacturing price for different speed chips in the same batch are the same. There are differences between, for example, the Athlon Thoroughbred & the Athlon Barton. Also, it is possible to "target" a silicon disk for higher speed CPUs at a cost of a lower total yield. But a single silicon disk makes a bunch of CPUs, and each CPU is tested to see what speed it can run.
A single disk can yield all high speed, or all low speed, but usually it's a mix of high, medium, low, and broken CPUs. The companies try to predict the number of each, but random and chance play into the actual out come. The "total yield" is the number of working CPUs. The "yield split" is the number of fast compared to number of slow CPUs. Problems occur when the yield is worse, in yield split or total yield, than expected, or better than expected. The first is obvious; the second means too many chips. Too many means a glut in the market, which can drop the prices too quickly.
Also, if the yield split is so good the company knows it can yeild anything faster (heat, power, internal timing limits for example), if the company releases all chips at the highest rating, in the short term, price for all high end chips will drop, driving down all chips at lower speeds. In the longer term, since consumers wouldn't see any more speed increases until design changes to fix the limit were done, there would be no high end chips to fill those "bleeding edge" buyers. The "earlier than planned" switch to the high speeds as the "normal" speed would mean the company would have "lost" the money it could have made if it decreased some of chips speed in this (and the next few) batch, and slowly ramped up, and slowly dropped the prices.
High yield splits have happened to both AMD and Intel. When they thought they could ramp up the speeds even further in the future, they didn't "under-clock" many chips; they tried to increase market share instead; when they knew they were reaching the limits of the current design, they "under-clocked" as many chips as needed to keep the profits up.
Huh, went a little too much there.

Review:
a) Costs are basically the same for high, medium, and low speeds. Unless tricks are done to increase the average speed, at the cost of total working CPUs.
b) Sometimes it makes market sense to release all chips at their max rated speeds.
c) Sometimes it makes long term financial sense to release some chips at rates under there possible max speeds.
d) Companies are in trouble if the yields are low.