It doesn't bend due to quantum effects, but quantum effect cause it not to bend over short distances. Also, several million times larger than 400 nm is about a metre. Are you trying to tell me that CD-ROM drives have a laser that is a metre long inside them? I'm not talking about the beam itself, but the apparatus which generates it.
So are you saying that if I used the laser out of a CDROM and shone it towards the horizon that it would not bend?
If it would bend, then you can do an experiment in your own home. Simply place two mirrors several meters apart (as you said the scale you would need is about a meter to avoid the quantum effects), or even 100 meters apart and bounce the light back and forth between them going form one side to the other (not up and down).
You should be able to use basic maths to figure out where the light beam should leave the two mirrors based on how much you think light bends and the distance the light travelled (which can be calculated by multiplying the number of reflections by the distance between the mirrors). Or more simply, using another laser to shine directly across the mirrors (as it is not travelling as far, if Bendy light is true, then this beam would not be at the same height as the first laser beam).
In fact, this could easily be done for less than $100 (for an apparatus about a meter or two long). All you need is two laser source (the laser pens would be cheap enough, if you can get the green ones cheap enough this would be better as their wavelength is much smaller than the red light ones and so would further decrease you problem of quantum mechanics), a flat piece of wood (use a sander to get it really flat), two mirrors and some things to fix it all together.
It would also only take a weekend to make and perform the experiment. Have fun with it.