2.) It's a position paper. It's not attempting to assert a novel invention from day one, it's staking a claim about the design space (and further that you should fund us to do research in this space).
3.) The project is ongoing, you can see some preliminary results on their wiki. Most notable are some details on very low latency RPC and very rapid recovery. The recovery work rediscovers the same essential prescription as bigtable but does so via a second sharding scheme, which I believe is novel. Whether it's better is open to debate.
Novelty or originality are not the only requirements for noteworthiness. A great deal gets done confirming prior experience or making relatively modest and obvious evolutionary extensions of previously well known work.
http://www.amazon.com/Gigabyte-GC-RAMDISK-i-RAM-Hard-Drive/d...
ZeusRAM SAS drive: http://www.stec-inc.com/product/zeusram.php
RamSan rack-mounted: http://www.ramsan.com/products/rackmount-ram-storage/ramsan-...
Kaminario K2 SAN: http://www.kaminario.com/products/K2-Solid-State-SAN-Storage...
acid-state currently lacks replication/multimaster support, but happstack-state has had several experimental implementations of that as well.
acid-state is Haskell specific.. but that is part of the appeal. You can directly store fancy algebraic data structures with acid-state. You are not limited to a simple combination of records integers and strings (for example).