Well, you have some rather conflicting requirements. I would suggest reading the strobist.com blog and a book like "Light: Science & Magic" first to get an idea of what sort of modifiers you're going to need to achieve the look that you want. The classic options are softbox and umbrella, but you probably want fresnels for the Karsh look. Fresnels (big flat stepped-surface lenses) are commonly found on continuous lights because they're so efficient (and continuous lights are not!), but they work equally well with flash.

Using your living room as a studio is pretty easy for modern-style bright portraits but it isn't really compatible with the Karsh look (lots of specular highlights, low key, dark backgrounds) unless you also go to a lot of effort in blocking out light not coming directly from your strobes (wall and ceiling bounce). Big black drapes will get you there though.

For 35mm, you don't need much light at all. A couple of moderately powerful (100Ws) hot-shoe flashes with basic modifiers would be quite sufficient, plus you can get TTL operation from them with the right cameras. 4x5 requires a huge amount more power: as a rule of thumb, the amount of light you need is proportional to the film area if you want to maintain a particular DOF in the final print. 4x5 has 12.5x larger area than 35mm, which means that to get the same DOF at the same ISO, you're looking at about 2500Ws of power. Of course, most of us just shoot with less power, bring the lights closer, choose a shallower DOF, etc, etc.

Personally I shoot (mostly 6x7 and 4x5) with a pair of Bowens monolights: 1000Ws and 500Ws (frequently, just one); that's enough power for most purposes and certainly enough if you're doing low-key very-specular Karsh-like light. It's way too much power for 35mm though unless you want to shoot Pan-F with 3-stop filters or something.