Hi mate ... the Thermite cases are 40 l each . They are really too big,especially too wide , but everything else out there was too small .The lids in the Thermite cases are good solid stainless trays that would be easy to rig as tool trays or tables .
I have a decent set of small BMW plastic cases but they are good for lunch and light wet weathers only .
Locking ? I couldn't come up with a quick and easy method and quite frankly those two hand wheels are very easy to reach from above .The cases have lock points outside .I forgot to mention that the main advantage of HDPE is that it doesn't rust ,it doesn't rattle ,it's light , strong and cheap .Apart from that it's no good at all ! If I could weld and bend it I'd make the whole job from the stuff .It's great .
The soft bag versus hard case debate is interesting .I can see advantages in both but I've slide the bike down the road on a big plastic box , my leg between the box and the bike . Other people call them leg breakers .
I'll keep watching your progress mate ...we await glossy pictures !