first off dont go stealing lights.Not worth the trouble and you arent going to get them working without a ballast.Even then your asking for trouble and possibly a fire risk.
You can use floros all the way through.Im thinking about it myself (125W envirolites) and money is no object but space is. I want to try with floros so I dont have to worry about all that heat from a HPS lamp and dont have to worry about a huge ballast either.

As for raising the lamps why not mount the lamp fittings on a piece of wood then fit whatever other mountings on the reverse side (hooks or drill 4 holes 2 either side and run some sturdy string through them) then just tie up or chain to the top of your growroom. The other advantage of floros is the weight.You dont have to worry about a heavy HPS or a heavy ballast