Generally my EDC starts out with a light and a tool, usually a knife but sometimes a Leatherman. I think of these two tools as the basics. I rarely add more than these two tools, but when I do, these are where I start. I have my gear organized into pairs of knife and light combos (light&saber). So why not combine the two into one tool? Because they usually stink.
Gerber released a combo tool, making something like an extra fat SAK; it is called the Gerber Fit. Here is the product page. Here is a good street value. Here is what it looks like all splayed open:
This just looks like a failing effort from the outset. The light is not too bright, the steel is Gerber's mystery meat "High Carbon Stainless Steel". The blade shape is non-descript and boring. It doesn't list the batteries it uses but I think they are probably some weak sauce button cells.
In part this is an underwhelming tool because it is from Gerber, whose quality control has fallen off a table in the past 15 years. I have two Gerber multitools and they are junk. They now reside in my spare toolbox and my wife's toolbox in her Chemistry Lab (my wife is a Chemistry Professor and needs to do a lot of tinkering). Both rattle and clatter like a horse drawn carriage. When in use they flex terribly. The second reason this fails is because of the design. It has clean lines when closed, but it compromises on both the blade and the light.
There are other combinations out there. Tool Logic makes one. Victorinox makes many. CRKT makes one (the Flux is a little different, but the same idea). None look like screamers though and if I had to pick the SAK would definitely be my first choice. Until the lights are worth their salt and the blades are taken seriously, these combination tools will be relegated to Black Friday loss leader bins.
One idea that has promise would be to combine a light like this with a blade of some use. 230 lumens, rechargeable battery, tiny handle sized package. Sign me up. Spyderco are you listening? Speaking of Spyderco they did combine the Jester and the Photon in a little package a while back. That seems good to me (LOVE the Jester's blade shape...much better than the Lady Bug).