Please look into ENA - European Nucleotide Archive.  I am not sure about the x-coverage you are looking for.  50X coverage is a kind of high mark for whole genome sequencing, till date I have not come across any study which reports such high coverage, But you can search in ENA. 

Hi

you could also look at the ncbi counterpart (https://trace.ncbi.nlm.nih.gov/Traces/sra/sra.cgi?view=studies) where you will have access to the tools and lot of NGS data.

fred

thanks Sourav, There's apparently any high coverage whole genome sequencing in this archive, but the good point is that I found several HeLa whole genome sequencing datasets with which apparently  I could get 45X coverage (by pooling all... )

Of course HeLa cells is not perfect but it will allow to do some assay

make an account with illumina basespace, they have plenty of data avaiabale for the gold standard genomes like NA12878