Casca:There's little or no chance of the Sky HD channels filtering down to Virgin, I'm afraid. Sky see them as a USP and a subs driver; they'd never dilute their offering by giving anything else to their competitor. At the moment, the sheer level of HD content is a real differentiator for Sky. Virgin don't have the bandwidth for anything like the level of HD channels available on Sky, either.
Yes, ITV HD will arrive on Virgin when their exclusive contract with FreeSat expires, and maybe C4HD will come on board at some point, but Sky will have the others tied up with water-tight long-term exclusive carriage agreements, so don't hold your breath waiting for MYV HD or Discovery HD, I'm afraid.
It's more that virgin have absolutely no intrest in providing HD services at the mo, the service has the bandwidth. Also like you say sky don't "have" to provide HD to virgin, unlike the regular channels which it's obliged to under anti-monopoly ruling stuff.
while the V+ is theoretically capable of triple decoding/twin recording the reality is it seems overloaded when doing so, recordings may come out with breakdowns when other channels are switching or stop/starting recording, and I've had the thing reboot itself in the middle of a dual record before now. It crashed both times I attempted to record 1 HD and 1 SD programme simultaneuously so virgins lack of HD services is perhaps somewhat irrelevant anyway...