Café de Nuit

What would a lich/vampmire be like? Or vice versa. Sound scary?

Sounds a bit counterproductive, to be honest. People generally become liches to avoid dying of old age; if they're already vampires, why would they bother?

Also, the "themes" of these two undead are very different: vampires are seductive and lustful, liches are terrifying and coldly-intellectual. Their motifs just don't go together.

I suppose you could have a lich/vampyre, if you really want to use the idea and have a vampyre IYC with sufficient spellcaster levels, but doubling up both undead templates isn't likely to work too well.