ISOs and rugged
This is something I've wanted for a long time. I thought that surely it was possible to have some drive electronics which can mount an ISO and make that appear to the host as a removeable optical drive to boot from, especially since telling the host a USB device is an optical/removeable/floppy drive is possibly just a USB class identifier. That's a cool feature on the Zalman ZM-VE300.
Would be even better if you could tell the host system it's a USB floppy drive though that's becoming less and less of a problem these days.
But what I'd really like is to see a company step up with something properly rugged for 2.5" drives. The Akasa Lokstor X21 looks like the best bet here. I've had a few of those Lacie ones with the orange buffers and they have been very good but I'd like something where you can bring your own drive and with more robust electronics. That, combined with an SSD, makes for pretty robust portable data storage. The weak point in that is the reliability of the SSD itself and I'm still not convinced. Having said that my next laptop purchase will probably feature an SSD.
The good news is that these should be plenty fast enough to run VMs. I quite like the idea of sticking ESXi on host machines and taking your whole environment with you.
Enclosures for those small form-factor mSATA SSDs would be great, as they tend to have the same capacity/speed as 2.5" drives but in a more compact package.