I've just started a new SRFI, SRFI 110, for "Sweet-expressions (t-expressions)". This SRFI creates an optional set of additional abbreviations to make s-expressions easier to read. In particular, it adds syntactically-relevant indentation when outside a list.
If you're interested, please see the SRFI page and join its mailing list: http://srfi.schemers.org/srfi-110/ The draft SRFI includes some comparisons to previous work, going all the way back to M-expressions. Thanks for your time! --- David A. Wheeler
