High Power Diode Laser
includes 1 watt diode lasers
If we can work out the optics, high power diode lasers might be an option. 2W, 808nm, $45:
It's unfocused, and I'm not sure how we can bring it to a point, but if we can solve that problem we could use the diode bars designed for diode pumped solid state lasers, which go up to at least 80W.
I'm not that interested in pursuing the laser sintering or cutting myself at the moment, but I hope that you find that useful.
Do you know more about beam combining of such lasers? The last I read - that was an intractable problem - see General Remarks at http://www.rp-photonics.com/coherent_beam_combining.html
From Viktor at RepLab Discussion List on Google on December 3, 2009:
... for single-bar-lasers you can use cylindrical lenses - for multi- bars you need tiled or multiple cylinder lenses or you can try with a fiber-bundle fused and tapered at one end forming a single exit and the other ends free or assembled to a fitting square atached to the diode ...
Some years ago i helped developing an assembly station for ring-focus- lasers, where e.g. 80 laserdiodes with 20 Watts output power and cylindrical lenses and uniform optical characteristics were aranged around a complex hyperbolic mirror and add their powers into a single focus-point - http://www.ringfocus.de/en_page/products/en_ringflaser.htm
With a bundle of glass-fibers connected to the output of the diode-bar you can do essentially the same ...