I think its an interesting concept if you can get JBoss to replicate the functionality of the OS and hardware behind most COBOL running on big iron but on low cost 'distributed' servers. Running COBOL is possible in non mainframe contexts already. Running COBOL with all the benefits of a mainframe without the mainframe cost and mainframe OS has not materialized. Its been surprisingly resilient to disruption so far. If you could offer all the functionality at a significant decrease in cost per mip, you would have a winner and a lot of fans (eventually as it became proven and big CIOs started to trust it). There are plenty of less critical workloads out there that could be migrated out though if they could access the same data cost effectively. What do you think the big challenges are?