One obvious and trivial way to allow for testing like this is to have boot -a also ask for an override of the module path.
This should not be too difficult, although it would (continue to) have the restriction that modules "pushed" from the boot loader (those which are loaded via /boot.conf as well as those automatically pushed for non-ffs boot-device file systems) would continue to be loaded from the boot device.
Once that is there, also provide the override via userconf or /boot.cfg.
Would this really be necessary? Do we have the ability to set the root file system via userconf or /boot.cfg? (Neither the boot.cfg(5) nor userconf(4) man pages hint that this is available?)
With a goal of improving the useability of kernel modularity, I'd be happy to implement this capability (WRT boot -a), if there's some sort of consensus.
+------------------+--------------------------+------------------------+ | Paul Goyette | PGP Key fingerprint: | E-mail addresses: | | (Retired) | FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com | | Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd.org | +------------------+--------------------------+------------------------+