dreambox 800hd or vu+ duo for the main room
the dm800 will set you back around £200 for a clone depending on where you get it from, you can find them cheaper if you don't mind shipping from china but there's always the hassle if something goes wrong, it only has a single tuner so you can't watch a channel and record another although channels on the same multiplex (frequency) are made available when recording but there's not normally much choice, i have one and it's a decent box
the vu+ duo is a hd box with twin tuners and costs over £300, i've seen them as cheap as £310 going up to just under £400
the dm500 might be the best bet for other rooms, genuine boxes are no longer made but you can find clones for under £50
for foreign channels you'll need at least an 80cm dish plus a motor, you'll also need a lnb with at least 2 outputs, 1 connected to the main box and the other going to the bedrooms and using a splitter, i don't know if this will weaken the signal too much so you might be best off with a quad output lnb and run cables to all 4 boxes, you need an internet connection as well for each box, the dm800hd can use a wireless adapter but mine is hardwired to the router so i'm not sure what dongles work and if the drivers work on all images, same for the vu+ duo, the dm500 has no usb ports so you need to hardwire it so homeplugs will be the best solution
i also take it you're looking at card sharing to cut down the costs? the main problem you'll have is that most people selling lines don't like you using them on multiple boxes so you'd need to find someone willing to cut you a deal if you want full sky on all 4 boxes unless you don't mind paying £40-£50 a month, the main server i'm on only has sky + espn & setanta ireland and has just gone up to £12 a month but it is glitch free on hd channels and is well worth the money, i was thinking of putting another box upstairs but i'd have to pay another £12 p/m for a 2nd line, i have a 2nd server i pay roughly £20 for a 3 month sub for which has all the foreign stuff on as well as sky but i cancel this during the closed season, i've seen servers as cheap as £7 p/m though but doubt they will be glitch free