Would a person with a higher body fat percentage store more of a fat soluble compound, or store for a longer time, than a person with a lower body fat percentage if they both consumed the same amount in the same time frame?
Does body fat percentage effect storage of fat soluble compounds?
Phenytoin, an anti-seizure drug, provides a good and well studied example. The key issue here is that, for phenytoin, plasma half-life is proportional to the apparent volume of distribution of the drug.
(Apparent) volume of distribution is a pharmacokinetic property of a drug. It is the volume a drug would need to be dissolved in in order to achieve the concentration of the drug in plasma. For fat soluble compounds, this can be quite large, as the drug is primarily partitioned into fatty tissues, leaving a low concentration in plasma. Empirically, phenytoin's volume of distribution is higher for more obese patients, and (by the same reference), the half-life is proportionally longer.
As is often the case, though, it depends on the drug. For some lipid soluble drugs, an increased rate of metabolism by the liver in obesity compensates for the increased volume of distribution; for others, obesity doesn't have that much of an impact on volume of distribution in the first place.