People have been building stuff like this. Often for firewall appliances (eg SCC Sidewinder, Immunix Linux, genua w/ OpenBSD). They usually do one of these: (a)

People have been building stuff like this. Often for firewall appliances (eg SCC Sidewinder, Immunix Linux, genua w/ OpenBSD). They usually do one of these: (a) get big under new management that doesnt care about either security or the little people (enterprise focus); (b) sell out to company like that; (c) go bankrupt cuz market values assurance of security the least. Sad but true. There's still a few companies selling microkernel-based solutions in defense and mobile with Linux user-lands. They'd OEM license their stacks for a new set of products aimed to do this. They cost a fortune. Whoever pays it wont get it back, though, cuz folks dont usually pay for security in that volume. So, nobody is doing it for small players for now.