Darth Mallwalker said:

I've been using SoX for SRC. By many accounts it's the best freeware solution, and second only to iZotope in the non-free category.

I've gone 44100 --> 48048 with SoX. Then using a hex editor, change 48048 to 48000 into the WAV header so it plays at the right speed.

[My reasoning 48048 is an integer, while "44056" is rounded from 44055.9440559...]

Yes that works also :)
You'll get a rounding error with 48048 as well though --
48048 - 0,1% = 47999,952
Both 44056 and 48048 are 'standard' though it seems.

CapableMetal said:

Interesting point, and certainly worth a try. The stretching is certainly done at 0.1% to match 23.976fps but seems to need very fine tuning as it (thus far) hasn't quite seemed to line up properly.

There could be small frame differences from the theatrical compared to the source you're using.

The quality of the rendered stretch in audition is actually very high, I haven't heard any artifacts on my test mixdown, and it preserves exact pitch too, although thats probably a silly thing to be worrying about as it'll only be 0.2 semitones out.

I'm sure it's fine :) -- 'possible artifacts'
However, less processing is usually better & I believe the standard way of dealing with this is simply slowing the audio down.