A main feature of 'cheap' LED desk lamps is the fixed and for the most part irreplaceable lamp.
Some time ago I researched LED's for photography and found that few manufacturers publish the spectra of their LED lamps.
The only one I could find was a local supplier (CPC Farnell) who list Kosnik GU10 lamps and publish the spectrum data.
http://www.farnell.com/datasheets/1782807.pdfThe 4000K version seemed to have the best available output with the least gaps, so that's what I got and they seem to work pretty well but GU10 lamps would I think be too heavy for the Ikia stems, they need a much stronger support, which kind of negates their usefulness for this task.
If one could find an LED chip with a known good spectrum then I am sure it would be entirely possible to install it in one of these Ikea gooseneck lamps. I have myself constructed a UV LED lamp with a Nichia 365nm 3W LED so I am sure it's no big deal with other LED's.
The trouble with LED's is not only are they either too warm, or too cold, they have massive gaps in their spectrum. Not sure if Michael will read this but one concern I have is when photographing flowers, esp. delicate whites that a poor light source like these 'cheap' LED's with un-determined spectrum must influence the photographic results and distort the natural colours, as compared with direct vision in daylight, bearing in mind our eyes have 'intelligent' white balance built into our brains. The camera only 'sees' the white balance which is set on the dial, the LED emits a distorted spectrum, yet we trust our vision of the photograph.
Given the vast expense of the lenses used for this type of photography and the huge debates between this lens and that, for the subtle shades, coolness and warmth etc. no account seems to be made for the light source, which to me seem to trump all the expensive lenses and fancy sensors, because the light is what is being recorded by the lens and sensor. They can only record what they see. In my opinion they are being starved of a full spectrum of light by using these 'cheap' LED's to illuminate the subject.
The lighting is probably the most important ingredient, yet seems to get the least attention and it's probably the cheapest to deal with.
Sorry if this seems a bit of a rant...