Its a fair point Emrr made in that using an unspecified connector might prevent you selling it or in the event of misuse ,no matter how stupid the opperator,you could find yourself in trouble . If its for home use or only supervised by yourself is one thing , in the event a member of the public is involved in opperating your equipment you have to engineer in 'idiot proof' as best you can , theres always the chance someone will plug a sub woofer into the HT speakon and land themselves the other side of the room like the scene from 'back to the future' . I did take the trouble to put a lightning flash yellow triangle 'danger of death' hazard warning on my speakon ht connector just in case any wise guys tried to use my gear in my absence and got badly buzzed.
Maybe there could be a simple way of modifiying a speakon plug such as a putting in locating pin/slot that would prevent it ever latching with normal use speakons . I think just to make things easier on this psu Im working on I'll just use cable glands for both mains and Ht/Lt wires ,cuts down on a lot of wiring , and allows you to run thick cables right into the supply
Caravan 7 pin connector might be ok even though its only rated to 12 volts ,not very touch proof ,big huge big contacts, might work well for LT supplies , and its very cheap