Hah, I meant distance from your camera to your flash gun.
I think you've nailed it with the kit list for your cable though. At least, that's what I imagined you'd need.
Having bought a load of camera accessories from Hong Kong dealers on eBay recently, that would be the first place I'd look. Some stuff came in about 3 days. The longest wait was just under2 weeks. Everything has arrived safely and everything works as advertised. There can't be much to go wrong with a bit of cable and two adapters. I don't think there will be any electronics involved -just basic hard wiring and a bit of solder, so I should think the cheapest source you can find would be OK. I dare say you can pay more and get better quality - perhaps locking connections that won't drop out, or just sturdier cable with more robust plugs, but for domestic use, there isn't much to go wrong (I hope).
If you're a gambling man you could try (risk) eBay wireless flash triggers. It would be a neater and less accident prone alternative to a snaking cable. I've had mine for about a year and hardly used them. I just fitted brand new batteries to sender and receivers and I've just about got three receivers (out of four bought) working sort of reliably. There is the odd surprise flash just to keep me on my toes though. I think nowadays there is a new design, which takes AAA battries instead of 2CRs for the receivers. Maybe they are more reliable, maybe not. It's just a thought.
Any other wireless solution is going to get far more expensive than eBay triggers, basically starting at £100 for an ST-E2 from Onestop-Digital in Hong Kong (battery extra), to several times that for Pocket Wizards, and a couple of options in between.
EDIT : Actually, brain just woke up - you could also try cheap optical triggers from eBay. Your popup flash acts as the trigger - just set it to -2FEC for minimal actual flash effect - and then pop an optical hotshoe adapter on each flash gun you want to trigger. The only thing to watch out for is that you get one that can ignore the ETTL pre-flash. I assume that is possible. The other thing to watch for is, so I have read, that they are rubbish outdoors in bright sunlight. Indoors they should be fine.