I have Ray Daniels book 'Designing Great Beers' and he talks about the grains the commercial breweries use for a Pilsner Urquell. They all keep it very simple - all you need is your pilsener malt, perhaps a bit of wheat for head retention, saaz hops for 40-50 IBU and a bohemian lager yeast. I did a brew this way and it turned out great. If you want to experiment you could probably add a bit of vienna or munich for some added malt complexity, or some carapils for body, some crystal for colour etc etc - the possibilities are endless. Sometimes the most simple recipes are the best. Use your pilsener malt and go from there.
By the way, a decoction mash would achieve the best result with added malt complexity but I don't think you need to initially.