This has been addressed with Ambrosia, mainly to help update, and either Andrew does not want to release Coldstone's open source outside of his circle of employees or he legally can't. I suspect he legally can't, as he got it from a different company, and I'm sure there were some legal stipulations when he bought it. Nevertheless, Coldstone's open source will not be released. Sorry.
Could Beenox be contacted/lobbied to release it? I thought Ambrosia bought all the rights, so they could do as they see fit. If not, does it revert back to Beenox? Do they have plans with it? Just seems a shame to lose this interesting piece of software.