Not enough PSU cables

I have recently built my pc, bought a 750w PSU which is ample, but non-modular – however I ham now struggling for power now I want to install a 3rd HDD – I’m using a single GTX280, which seems to be using 3 or four power cables alone to fill the splitters that came with it, it uses one 8 pin connector and two molex connectors to make up the splitter supplied with it. other than that I have a sidefan, 2 front intakes, a rear exhaust and one or two more expendable fans for HDDs etc. *will check the exact setup when I get home but the gcard uses several psu outputs alone and there aren’t very many*

I am not sure how many devices you can piggyback onto the one output from the PSU – for fans I’ve wired four, but for HDDs & my DVD-RW I have kept this at two (and devoted the required outputs for the Vcard) – Can I piggyback 3 HDDs onto one molex using two Y-splitters?

OR shall I try and find a splitter to share the one HDD (vraptor) with one of the outputs going to the graphics card?

The HDDs are a Spin Point F1, a 300gb Vraptor & a generic 250gb Samsung – don’t know if the first two will have a higher draw than normal.

Your input would be greatly appreciated, as I cannot find any advice on piggybacking/splitting PSU cables safely or effectively.

Cheers mate, will be redoing the cables tonight - all I'm praying for is that I can infact get a 3rd sata cable seated under the graphics card.

Will probably have to do a fair bit of shuffling around to find a spair - I'll find out what brand my PSU is so that I can warn people, I think it's a Hiper - strange thing is that it's branded SLI/X-Fire compatible when it stuggled to power up the one ruddy card!!!