I've decided that my preferred storage configuration for the raspi is to have a very small sd card and root/everything else on usb.  This has several advantages for me :

1) Large storage is cheaper on usb

2) USB is more portable, and I can read it from a VM (where I have had some issues reading built-in SD card from VMs)

3) I can reimage an sdcard without losing my data if /boot is all I store on it

4) it's easy to keep a working fallback kernel on a 512M boot sdcard.

5) I don't like the SD card sticking out the way it does - so I am investigating using RSMMC (this for example) but they are notoriously slow.

Other half-length card ideas include this half length adapter from ADAFruit and the card adapter from quilix which both seem very promising.