Making a small dual sided linear PSU, unsure about connectors and casing

[Plecto]

Hi. Since it's so hard to find a dual sided wall-wart I was thinking that it's easier to just make one rather than getting my device to run off a single sided supply or bother with virtual grounds. I'm unsure of what kind of what casing and connector I should use though. It's going to supply about 2x200mA at +-17VDC so it isn't going to be that big. I've been trying to find the connector I can use between the psu and the device, but I'm only finding three pole XLR and S-video connectors, but they aren't really ideal for this purpose I believe. Are there a standard three pole connector that are used for these purposes? Like a three pole variant of the standard DC connector perhaps? I'm also wondering about what casing I should use. I have a bunch of casings that have the right size, but they aren't that rigid. Is it perhaps possible to find 'empty' wall-wart casings with just the 230V pins sticking out of it? I live in Norway so it has to be of the European standard. Putting the psu inside the enclosure of the device isn't an option by the way