For Saints to mix it up with the megaclubs, we would have to leverage some of our highly prized assets. eg. Sell Shaw for 25m, hope to find a replacement (or Targett) for 5m, and put that 20m somewhere else.
It would be highly risky though. Even with all that transfer money, we still may not be able to find players who want to play for us. And if it doesn't work out, we could be totally screwed.
Failing that, I think we could make a good run at Europa with just a good CB and one attacker. It would have to be someone who can score, but it doesn't have to be a striker, IMO. I think Rodriguez can play up there. It could be a good winger or maybe a Michu-type top play behind Rodriguez. And if we do that, then we'll generate more revenue for transfers. Between that and maybe the lesser sums we might get from Osvaldo, Mayuka, perhaps Ramirez we could leverage that into some better players.
The latter approach would allow us to slowly boot-strap our way up the League instead of going all-in. It's less risky in some ways. But OTOH, if you are looking at a 5 year window, a lot can happen. You'd have to be sure you could hang on to Shaw, Pochetinno, etc. as you build the "supporting cast." Otherwise you end up just spinning your wheels.