MacPredro: That's an excellent idea. I doubt if "strong glue" would do the trick for long, but heavy stitching sure would. If you don't have access to a suitable sewing machine, you could hand stitch it or take it to a shoe-repair shop and they'd probably do the job for ten or fifteen bucks, including straps to hang it from. That's still less than half what you'd pay for a cheep manufactured bag. And it's actually more authentic. I mean, do you really think those hard-training guys back in 19th century China bought their wall-bags online or at a martial arts supply store?
BTW I had to take my bag to the shoe repair shop anyway after the hanging grommets ripped out. I had them stitch on some nylon straps with hardware-store D-rings instead. So far, it's holding up great.