I have shopped around alot after waterTIGHT connectors, and have found some that is available in 3, 9 and 25 poles. They are available from www.rs-components.com Look for stock numbers 452-114 (9 pole) or 184-9323 (25 poles) There are also a 3 poled version, and you should be able to see it once U find the others using the search facility. The plugs are not for many amps, but surely they can handle servos etc.
Notice that contact pins comes seperatly in some cases, and that it is not nesercary to have the special tool to mount the wires to the pins.
The link I have given U above takes U to a site where U chose the closest branch of the world wide business of RS Components. If U have further Q's about them, please feel free to mail me, address below.
Yours Sincerely, Robert Holsting, Denmark
1/81 SSBN Ohio Class scratch builder, more at www.robse.dk
"Never be afraid to try something new; remember that it was amateurs who build Noah's Ark, and professionals who build the Titanic"