I'm with Don. It's unfortunate, but the benefits to OpenACS 4.x porters of making such a change would be more than offset by the pain for OpenACS installers, who would need to recompile PG and then do an initdb using the modified version. There will hopefully be a lot more
OpenACS 4.x installers than porters...
Given the interest in "better out of box experience" in recent posts, forcing a PG recompile looks like a step in the wrong direction.
Is it worth re-asking the PG folks about this, ready for PG 7.2 or 7.3 or whatever ... so at least it could get onto their agenda for some (distant?) future PG version? In the 'many months' since it apparently first came up, hardware has got still faster and still cheaper, so maybe the case is now sufficiently strong?