Could one LED each of those be cranked up in wattage to actually deliver noticeable heat? I'm thinking at least 25W or more?
I presume you're talking about an entirely different unit here. 25 watts is entirely doable with LEDs but not usually with a single LED.
If someone is actually willing to come up with plans for a programmable unit like this .......
Programming for the microcontroller is the easiest part of that build.
Fantastic. Can it be done with perhaps 4 LEDs, close to the wavelengths I mentioned above (605, 655, 715, 835)? And yes, I'm talking about a separate unit. If this can be done easier, cheaper, and quicker then I may forego the laser unit for now and try this out first. If not then an 835nm laser would be my choice.
That's really great. I have other ideas but it might raise the bar a bit. For now I should probably just stick with the LED and LD units I have in mind. When I said "programmable" I meant something where the frequency of the pulse could be programmed into the unit manually. That's a whole other animal, no?