I would like to do this for a U110 ideapad also. In the BIOS, there appears to be the ability to select "external device" in the boot order, but I have no idea if this will work for the ExpressCard Slot.
In addition, it would be good to know if thiscan be done via the SD card slot? Of course, if we knew for sure whether the SD slot on the U110 supported SDHC cards, that would be a good start (no-one here seems 100% certain). If it supports a 32GB SDHC card, that would be a good start to trying to boot from it.