Cat's statement was pure fact. The majority of Li-Ion powered bike lights with external battery packs use "Magic Shine style" connetors. As also noted, it is an extremely common connector for DC powered devices that use wall wort style adapters. Within an arm's reach of me are my router, network switch, and small linux based video player that all use that exact same connector (yes I tested them with a MS style extension cable).
It probably IS far easier to list brands that use some other connector, than list all the ones that use the MS type connector. I'll start.
Previous models of Xeccon lights used the MS type connectors. Some of their latest 2013 models use a different, Square connector. Lenorad noted that, going forward all models will move to the square connector. The actual DC connection looks the same, but the plastic barrel surrounding it is square. It is unclear if the standard round connector will fit in that square hole, but if it does, I suspect it will be less secure, and more prone to water infiltration. Xeccon does have old style to new style adaptors.
The SolarStorms use a slightly different style connector. While it is plug compatable with MS, it is (in my opinion) superior. It includes an O-ring on the male end, and an external screw on cap that joins the male & female parts together. The combination make the connection more weatherproof. I often do not do up that external cap, and it works just fine.
Lupine is a different connector. It appears to be based a connector fairly commonly used in electronics. The "electronics" versions are not waterproof.
The Light & Motion packs seem to have a 4 (or is it 5?) pin connector. I suspect the lights are incompatable with MS style batteries. They appear to be based on a 3S1P & 3S2P design (as opposed to the MS type 2S2P).
The Shadow BL-20 uses a 2 pin screw together connector. I think I have garden lighting with that same very weather resistant connector.
As you know, many of the self-contained lights are using mini-USB or micro-USB connectors for charging. Personally I don't think those connectors are durable enough to withstand long term usage. The micro is reported to be more resistant to breakdown than the Mini.
Andro, I didn't see a close up of the Dosun plug in any of your postings or videos. I had to spend a bit of time searching the net for one. Is
this a picture of the Dosun connector?
I think in most cases you may have to cobble together your own adapter to non-standard connections. The problem may be finding a source for that connector. If an extension cable for your "other style" lights is available, it would be fairly simple to cut and splice of an inexpensive MS type extension cable and "other style" extension together.