Summarising recent experiments ...
No getty on tty1
Does not allow Shift+PgUp after boot has finished.
Commenting out the tty1 getty line in inittab does not result in tty1 being used for the graphical display manager (xdm on the test system) as suggested in the OP and does not, of course, display a logon prompt. But Shift+Pg does not work as it does during boot either. Perhaps the keyboard is switched from tty0 (console) to tty1 at the end of boot; it would be interesting to know how that works.
bootlogd creates and populates /var/log/boot providing:
- /var/log/ is accessible when it is started.
- The kernel is started with a valid console parameter.
- Tested on Slackware 13.0 32-bit with bootlogd 2.86 and /var on a separate file system.
- bootlogd works with kernel parameter vga=791 (tested. There are reports, not Slackware-specific, of bootlogd not working with frame buffers).
- bootlogd will create /var/log/boot if it does not exist (tested. At least one version of bootlogd does not create it).
- If bootlogd is running at shutdown, it logs console shutdown messages up to "Unmounting remote filesystems" (tested. bootlogd was left running from startup to shutdown).
- The bootlogd man page says "If the logfile is not accessible, the messages will be buffered in-memory until it is" but test results did not support that; the earliest bootlogd startup that logged messages was in rc.S after "Mounting non-root local filesystems" and before the second swapon.
- bootlogd was not seen to log any activity on tty1 (there have been reports that it does so, including capturing passwords entered during logon).