I now belong to the 30000 feet Ableton Live Warp club. It’s quite doable, all you need is a good set of headphones. I spent most of my trip over to NY from SFO doing this.
In my case — most of my time is spent to chop the song into reuseable clip parts, the warping itself mostly takes a few minutes. I have a couple of techniques. With Ableton Live 6.0, I start by just letting the application do the first cut. Then in most cases I have to adjust the starting warp point (1:1:1) — Ableton 6.0 seems to even do a worse job than 5.x for this. Anyway, if you find a really good starting point, exact (zoom in), and then you define a 4-bar loop, and jump the loop point around, for example quickly to the end. At the end, just do a hopefully small edit to adjust a possible end warp point. Then like a rubberband, most of the other bars will nicely align.
Also, when doing warp matching, by trial and error, and long time warping, you start to read the waveforms and see how they fit in. Based on the music, for example straight tech house, the kicks will show up easily. With other forms of music, the waveform might look very messy, but you could learn to read the peaks and know that they should align up with the bars.
Another technique I use a lot with warping is to set the beginning and end points, and then go backwards with the loop and possibly adjust settings.
All this should not take that long. The problematic songs, with let’s say an ambient start and no real beat, I just find the first part with a decent beat, and set that as the 1:1:1 warp starting point.
Nowadays I’m also editing the clips to avoid any funky half bar breaks and so on, they are nice, but for mixing and matching clips, they are a pain.