I could be dead wrong on this, but I read somewhere that the brewery that makes Delirium Tremens (Brauerei Hyughe) uses a blend of 3 yeasts for this beer. Denny could be right about making a perfectly acceptable homebrew homage with the Ardennes yeast, though. Belgian (and other) breweries many times arrive at their “house yeast” by virtue of re-pitching and selectively blending yeasts to promote the character they want to achieve through their fermentations.
Somewhat off topic, but I have been brewing 10 gallons batches for the past 15 years or so, and always split my wort into two fermentors and pitch two different yeasts. For my Belgian ales, my favorite yeasts have been the Dupont, LaChouffe, and Westmalle strains, in that order of preference. Caveat: O do not aspire to recreate a beer, just something Belgian/Trappist. The fruity notes of the Dupont strain is the winner for my taste buds, although the spicy phenols of the LaChouffe strain are a close second. I find the Westmalle yeast to be a good balance between the fruit and spice, but both are somewhat muted together. Still, it is the general work horse that I always use when I am brewing to entertain a crowd.
Back on topic, I concur with the LaChouffe (Ardennes) strain recommendation for a DT clone.