By rewriting the script to use git fast-import instead, it's now chugging along nicely at ~12.5 commits/s (ie ~47 minutes).
An almost useable export of Pike is now available from git://pike-git.lysator.liu.se/pike-new-alpha2
One known issue is commit 4435a84964353881596269079577725c1c9951e3, which is due to src/test/.cvsignore and src/test/create_testsuite not having been killed properly in the transition to Pike 7.2.
Another issue is that all commits are currently credited to the committer (ie not necessarily the author). I'll try to extract the information from git://pike-git.lysator.liu.se/pike.git.
Feed-back appreciated.
/grubba