Lots of LED strips: consistency?

I'm working on a project to sequence a number of red light strips into a jumpsuit, and I'm considering switching from my plan to use EL wire to instead use LED strips, spaced ~1cm apart. The current design has 17 channels, 22 segments.

My question is: how consistent are strips in terms of brightness and color? I will need 10-15 m of light so would use an port expander (NXP PCA9685?) with PWM driving MOSFETs, so I could calibrate for different brightnesses between LED strips, but want to make sure I'm getting the same wavelength.

There's no shortage of very inexpensive LED strips on EBay, any recommended vendors would be appreciated! DealExtreme has a lot of options too.

Any other suggestions on how to approach this?

Thanks!

but want to make sure I'm getting the same wavelength.

?? Wavelength is colour. This is not affected by voltage or current but by the LED itself. The better the LED the more tightly is the colour control. Some LED manufacturers sort them out into bins to be consistent. Cheaper ebay suppliers buy bin ends or assorted lots.

either get them from a reputable supplier or take your chances on eBay, either way just ask for them to all be in the same batch where i work we have been selling them for several years and i can take one of the old strips and compare it to a new one and you can hardly tell the difference but as led's get more efficient their color and brightness will change a bit so it's best to get them from the same batch just to be sure