Apple certainly have a well organised/optimised supply chain.
However that point can be overdone/exaggerated. Latest prices for Asus' Transformer pad and docking station (for example) at Amazon.com are $352 for the former and $125 for the latter - all up at $477, the whole package is *within* Apple's price-point and is selling very well in both the US and Europe (the prices in Europe are as usual a bit higher the package being equivalent to about $545 excluding sales tax though it is all the same selling well here even with sales tax.). A reputable OEM *should* be able to do this and make a profit as long as they do the necessary heavy lifting *and* do not expect to be able to imitate Apple's margins which are currently the largest in the sector.
The combined transformer/dock package is selling at Amazon.co.uk at a price *inside* that of the 16Gb iPad2 (prices include UK sales tax).
In other words it most certainly *can* be done if the OEM understands his business.