Possibly the smallest & lightest is the Genz Benz Shuttle 10T cab, available [url="http://www.bassdirect.co.uk/bass_guitar_specialists/Genz_Benz_Shuttle_Cabs.html"]here[/url] from BassDirect.
Still pricey at £420 delivered, but puts out an outstanding amount of sound, and weighs less than half (16lb compared with the Bag End's 33lb).
I've got a pair of TC RH450s, with a Genz Genz NEOX212T as a main speaker but, to be honest, after hearing the STL-10T, I'm almost convinced that I could just about get away with gigging with that alone! It's certainly got all I need for small gigs & practice!
The great thing is that, even with my middle-aged weak back, I can go anywhere with bass in one hand, cab in the other, and head in a bag over one shoulder - no problem - single easy trip from the car. In fact, each of the three items is a similar weight, with the bass gigbag possibly now being heavier than the head or the cab!
I'd be fascinated to hear their 8" cab...
Was very tempted by the Promethean for a home/practice/backup amp, but ended up going this route so that I had the same amp as my stage setup and, although it's cost me double, that's soon forgotten & I'm a happy puppy!