There's no overlap between denpa and vocaloid; I think you'd have a very difficult time having the vocaloid sing out of tune in a charming way.

ななひら (nanahira) is probably the most well known denpa artist, but she mostly sings normal songs now I think (and has a lovely voice doing so).

ココ is my favourite denpa artist https://youtu.be/2wl8Ofce8TE