vB4 Reminiscent Styles?

[Dave]

There's a premium "Metro" theme you can find on Themeforest which looks kind of the same on vBulletin 4 and 5 which you can give a shot.

If you want a true vBulletin 4 default theme for vBulletin 5 then I don't think such theme exists. If you want most of the templates to look nearly identical as the vBulletin 4 default theme then that's a lot of work with nearly no payoff.