Hallo LL! You're speaking about a guess i've had few time ago. for this I followed the Kirk Tuck's way explained in "Minimal Lighting. Professional Techniques for Location Photography" published by Amherst Media.
He explains how to build a lightweight and very carriable Studio (even if of relatively low power) with a Speedlite Camera flashes set. It'a strategy based on flexibility, portability and low costs compared with the hight power studio flashes (and hight prices and heavy weights) normally used.
I have found this strategy very interesting and fully usable for a lot of situations, and I was able to find all i needed on ebay cheap shops (I'm not able to find too much differences of performance betwen a Branded polyester softbox and a China Made Polyester one...)
My usual equipment reportage and fast response configuration is a speedlite flash only, housed on the Camera side by a Canon SB-E2 bracket, used with a Plastic diffusor and the flash head oppotunely oriented. This for fill in and lowered power flash use only.
To do something more in the Studio Lighting World according my opinion you have to use a heavier equipment. (Heavier but very light indeed: you'll be able to carry it everywhere you want and have a relatively good performances in almost a lot of situations. You can preview to use almost 3 Canon 580 EX Mki/MkII (the 430 cannot be used in junction with the CP-E4 Flash external Battey in order to fasten the re-charge) with 3 Manfrotto compact stand 001B and 2/3 Softbox Kit for speedlites (don't buy too much little softobx unless you don't wast to use them only for face and half-body portraits, minimum is 24") and/or an Umbrella (the same, consider almost 39") mount. Up to you, can use a Manfrotto 314B (or similiar) carriable background system. For Ettl transmission between flashes, Pocketwizard wireless system is the best, but is very expensive. So you can use a Canon ST-E2 Transmitter for relatively close distances use. If you want something cheaper you loose ETTL connections (Manual settings only), but you'd be able to find on ebay a lot of Chinese Made trasmitting/receiving kits.