It's probably not something you want to do because it's closer to daytrading than mining, but buying stocks from other mining contracts ("PMBs") when they are blatantly undervalued and selling them when they are more attractive, while taking the PPS mining profits in between is something that has proved to be a valuable short/mid-term investment strategy as far as I'm concerned.
As for hardware purchase, I would hold the funds until September. We are in uncertain territory right now.
PMBs are absolutely not the way to go. We will always get better price performance from owned hardware. PMBs are for people who don't have their own hardware manager - which we do.
I think it might be worth considering hedging our current hardware and any future orders with Difficulty Futures and/or DMS.SELLING shares - which I'd be happy to discuss with you (creativex) if you're interested at all.
I'd suggest bM be nimble enough to act with purpose if, for example, the 1st and 2nd Gen ASICMiner blades are priced competitively - having actual hardware hashing is more valuable than any pre-order.
Disclosure: I've recently liquidated the balance of my bM position that isn't currently leveraged. I consider myself likely to re-establish the position in the near future.