I am not aware of a plugin that does this, though I am sure others on the forum might be able to come up with a neat trick or two?
How so? Do keep in mind that you can alter the subsampling depth with qiime demux summarize by adding the --p-n flag as shown here.
Also, keep in mind that the FASTQC plot will be different, as it bins some of the positions unlike QIIME's built-in quality plots. For more details see: