Problem is... we dont know what the deal was or if even there was a deal... VF4 got ported in 2002... six months after xbox's release so Sega was already committed to the port prior to xbox's release... however, knowing a little bit about Sega's history, the arcade division always prided itself on releasing their flagship game on the best hardware possible.
VF4 Evolution could have made the jump to the xbox hardware but somewhere the wires got crossed and imho Sega missed out. Sega and VF5 went up against Tekken, SoulCaliber and DoA on PS2, where there were already established fanbases of those particular games with gamers who NEVER had an interest in VF5 and summarily dissed it out of hand prior to its system debut.
As to whether VF5 will come to xbox hardware... it may not really matter. Prior segaphiles such as myself made the jump to Xbox in hopes of Sega jumping with us... since they did not make the jump wholeheartedly (even though Orta and GunValkyrie were great games) they basically have been left behind. VF5 is in no one's top ten list of most wanted games on either system and its Sega's PREMIER title. PSO and Sonic have both become "milk" titles and both suck. That says a lot for their ability to understand the market and prosper...
Sega could disappear and really no one would notice...
) or praying for forgivness as we burn a copy of Last Blade on DC. 
