hmmm...that's an interesting one. The only thing I've done on my high tech nano is subject it to a 2-3 day black out, doesn't hurt anything. Also I routinely dose macro and micro on Fridays, because I'm not around my tank on Sat and Sun, and if its a 3 day weekend, I dose an extra amount for that day I won't be next to my tank.
One idea I read somewhere is just dose all your ferts on 1st day. If your tank is super dense and plants are growing well, I would think you could get away with it. The only stressing item for fish would be your nitrates would be pretty high, I've gone as high as 40-50ppm, I believe Tom Barr has gone higher. If your fish are healthy, I don't think it'll be a problem.
You'll get an algae bloom if your tank runs out of ferts, or your co2 goes haywire with the same light intensity.
another idea, setup some sort of drip dosing for your ferts. You'll have to time your drips and do some math, but its an option. Maybe poke a needle size hole in a 2 liter bottle cap, and see what happens.
Personally, what I would do is just dose the entire week's EI dose after a 60% water change on the day you leave and maybe knock back the light intensity and duration a bit if you fear you'll run out of ferts. adjust your co2 schedule accordingly too. I've never tried it, but that's what I would try. Good luck.
Oh, and watch out for evaporation and how your filter outlets are positioned, you don't want to agitate all your Co2 out of the tank at the end of week, cause then you might end up with an algae bloom.