As a pedestrian (no car) for my last gig, my case (Conn 62Hi) almost crippled me. I knew that I would have to find something consideralby lighter if using public transport again.
After much deliberation, I opted for the Protec C245X Gigbag for Bass Trombone. It is extreemly light, very well padded and can be carried on your back as well as by hand. There is also plenty of extra room for all your extras; mouthpiece, slide lube, music etc. and was very reasonably priced.
Other extras I decided I would carry seperately (Trombone stand, music stand, mutes and lighting) rarther than have them attached to the gig bag.
I have to say, I am delighted with this purchase.