Can bitcoin clients running on several home PCs get access to the same wallet and transaction database via a fileshare?
Bad idea.
I want the same wallet on all my PCs and I do not want to re-download 135000 blocks on every single one of them...
Clients or servers? Clients can access your single server with JSON. If you want more servers, you can either copy the block chain database, the wallet (really not a good idea, either
), or point new installations to your existing local server. They will download locally from that one.