I’ve been using Vocaloid for quite some time now.
I still have a long way to go before actually mastering it but at least I can manage to get the voice sound right, with special vibrato effects.
Here are the results. Basically, I’ve made them just for fun.

Trust (TV version) (Salia) [Hatsune Miku]
Dakishimetai (Mr Children) [Megu]

For Dakishimetai, I had to reproduce the interpretation from Mr Children’s PV, since I didn’t have the karaoke version. It was quite a pain because their guitar interpretation is quite unique and I didn’t have the right guitar sound patch.
For Trust, I realize even today that the pitch isn’t quite right. Maybe I’ll switch to Megu since I just love Nakajima Megumi’s voice.