My current interest in Medieval theology has taken me most recently to a series of lectures given at Westminster Theological Seminary by Dr Carl Trueman. These are available from WTS on the iTunes U. These 11 lectures look at Anselm, Bernard, Aquinas, heresy, mysticism, etc. They are quite thorough and are marked from time to time by the legendary Trueman humour. They are in a league with the previously mentioned lectures from Douglas Kelly given at RTS. I'm not sure how old the lectures are but some of them contain an instruction to turn over the tape (!) so they can't be hot off the press. There is also some sort of problem with the audio probably caused by the recording being voice activated. You cans till get a lot of these lectures nevertheless.
Bonhoeffer uses a similar phrase 'worldly Christianity'. It's J Gresham Machen that I want to line up most closely with. See his Christianity and culture here. Having done commentaries on Proverbs (Heavenly Wisdom) and Song of Songs (Heavenly Love), a matching title for Ecclesiastes would be Heavenly Worldliness. For my stance on worldliness, see 3 posts here.