It's actually not much of a pain to spin two spindles full and ply them together :shrug: ...you just put the yarn on tp rolls, punch some holes in a box (or use a basket) and put skewers through -- voila! instant lazy kate!
Here's a picture of what I'm talking about: Lazy Zib (scroll down)
I've done a fair amount of navajo plying with my spindles, and after the first time (which was very frustrating and I swore I'd never do it again ) it wasn't as cumbersome at all. The thing about navajo plying is, you lose 2/3 of your yardage (vs. half when you do a 2-ply). It looks so fabulous though!