It's very good idea - I will gladly use it myself, sounds like best bullet-proof solution for this.

@peterleinchen
As I've written, way of doing ti via /etc/event.d/ script isn't bad at all, but it got one drawback - boot time is considerably slower, as Maemo need to enable eMMC swap first, then, via Your script, enable microSd swap, and disable eMMC swap. As - at this point - some thing are already swapped (most likely, You run event.d scripts after starting hildon-desktop), they need to be moved from eMMC swpa to microSD swap.

As for using microSD swap together with eMMC swap, I don't recommend it, even with higher priority for microSD swap - it's still "in use", which creates (less, but still), I/O rade with things from optFS. Also, I'm quite sure, that using loopback file for swap is considerably slower than native swap - as it's with ED loopback image or native partition.

@BertvanDorp
5 minutes guide to using swap on microSD:

1. Reformat microSD card to contain linux type swap partition, by any tool You prefer (linuxbox/linux LiveCD via GUI tools, or on-device via command line, or on-device via Easy Debian with GUI tools, or...).

For this example, we assume You got 2 partitions on microSd card - first one is regular vfat, and 2nd one is linuxswap.

2. Use any method mentione din this thread to make device into using swap on /dev/mmcblk1p2 (you can edit /etc/event.d/rcS-late as suggested by me, or prepare script put into /etc/event.d folder, or wait for Hurrian to post his script and mix it with my way, or...).

You're done.

/Estel