I don't know the availability in Prague but I have Been using a Tamrac model 787 for years for medium format although it is completely adaptable to most formats. It is also adjustable to one's height. I can comfortably carry it fully packed with my normal traveling set up of 2 MF bodies, 3 lenses. a light meter, filters, GPS, 20 rolls of film, a nylon shell and a few other goodies all with the pack weighing 30lbs. (I'm 73) It also fits in an overhead airline compartment. It's dimensions are 27x15x50cm and is front loading. It's not cheap approx. currently $440 but neither is the equipment you want to protect as well as comfortably carry.

http://www.jeffreyglasser.com/