FreeSWITCH now compiles in AsLinux:

http://www.astlinux.org

AstLinux with the new bootloader Runnix (or you could just use
syslinux) boots from flash.  It also boots from PXE, ISO, disk, etc.
Pretty much anything :).

FreeSWITCH (compiled against uClibc) is about 3.3MB and as Tony
pointed out, mod_sofia is 1.2MB of that.  The sample configs and
sounds are much larger.  Luckily the sounds compress well with
something like squashfs.

Put it this way:

- Default AstLinux install (quite a bit of stuff these days)
- FreeSWITCH (default mods + mod_xml_curl, -spidermonkey, but w/ lua,
snom, vmd, and others)
- Sample configs (pretty big too but also compress well)
- 8k Sounds (HUGE, but compress well)
- Native sounds (G723, G729, GSM, PCMU, PCMA all 8K obviously)

 Results in a squashfs disk image of about 41MB.  You could run off a
64MB flash drive and have plenty left over for your union filesystem
(configs, etc). :)

 Be aware that if you are going to run from such a config we
recommend the default (which is to run AstLinux from RAM).  Otherwise
you take quite a hit reading audio from a squashfs filesystem.

 If you want an ISO to boot on a generic machine (VMware, virtualbox,
etc work too) let me know.