I wouldn't chance it. With the Chinese H1N1 screening taking 20 minutes minimum prior to deplaning and then lineups at PVG customs - you won't have enough time. I'm assuming that you don't have a Chinese Visa because you are transiting and that usually adds another 10 minutes to the process (since PVG does not have a dedicated transit line - unlike PEK which does).

I flew NH biz last week on a 767 - nothing to write home about as it was much like the pre-XM'd AC 767-300's. With SQ it depends what aircraft you get. If you are on the 380 or 777-300 from HKG to SIN - you're in for a treat with the fold down beds and HUGE business class seats. The new'ish 330's which SQ uses for intra-Asia flights are also OK but not as good as the 380/773. The 777-200's seating in business is not as good as they are simply reclining business class seats. Cannot comment on the new UA seats nor on FM (although their lounge has a nice noodle bar!)