It one is going to play with obsolete languages, then wouldn't Algol 68 be a better pick? At least it has types beyond "cell".

Or is the idea that BCPL is quite close to the bare metal?

Algol 68 Genie: https://jmvdveer.home.xs4all.nl/en.algol-68-genie.html

See this, code starts on pg 11: https://jmvdveer.home.xs4all.nl/learning-algol-68-genie.pdf (after 18 pages of preface)

See this for how BCPL begat B which begat C: https://www.bell-labs.com/usr/dmr/www/chist.html