Interesting direction, and we've had similar effects here with Velvet users for a related type of tuning.

And the very guy who contributed Velvet first, was amazed to see that this works:
`time eb Velvet-1.2.09-ictce-5.3.0.eb --try-software-version=1.2.10 --try-amend=versionsuffix=-kmer63 --try-amend=makeopts=MAXKMERLENGTH=63`

Of course, you can do similar tricks with `configopts` above; advertise it guys, because here EasyBuild rocks!!!