A lot of people promote exactly that, use a random SMPS for LED's.
I just finished a project with a customer for an Audio Power system, that starts with a "random" 350VA/24V SMPS and creates 12V Aux, +/-15...21.5V adjustable and +48V.
Using Multi-phase clock synchronised 750khz switchers the system has ~20mV P-P ripple at 3/6MHz and design output current BEFORE the LC filters on the output.
And due to the number of parallel converters audio band noise is also very low, as we get noise down on the general noise levels of the bandgap references, so we get less than most 3-Pin regulators..
That cleans up all noise from the original SMPS and creates a high efficiency "Audio Grade" supply for large mixing desks that can take on pretty much any Linear Supply and don't get birdies from interference between different switching frequencies of multiple SMPS.
Sadly, such systems are way beyond the capabilities of the average hobbyist, so I normally recommend linear supplies where possible and to use heavy LC/RC filtering over electronic power supplies, as they are less likely to spontaneously explode than 3-legged fuses.
Thor
