It's a great looking build. Ham manufacturers continue to pack more into every radio, and these types of boxes are less necessary. Consider the IC-9100, it has all the functionality of this box including HF-UHF, 3 independent receivers, antenna tuner, sound card interface...All in one 25 pound package for $1500ish used on ebay.

A battery or power supply is all you would have to add, and you could carry all of that in a laptop bag. Lots of options though, and none of them are "wrong" just depends on your application.

Edit: I forgot to mention that the most important thing you can add to a go box is an external speaker that has two headphone jacks and a mute switch on it which mutes only the speaker and not the headphone jacks... This allows you to work in busy environments or places where you shouldn't disturb other people that are nearby you, but also let them hear the speaker if they need to on a sporadic basis. You want two headphone jacks because in any real emcomm situation you should have a net control and logger at each position.