I'll through out a handful... regardless, I think a multisyllable name would prob'ly be best. Plus, it would all depend on what your family name is. You could also make it a middle name and simply have him use his middle name
Luke:
MichaelGrahame (
Graeme)
ChristopherSilasSolomonEdwardJonas (pronounced yonas... it's European)
Jonathan(if
Luke was a middle name in this case, it may lead to Jon-Luke jokes in reference to Jean-Luc Picard... thought of that after adding it)