From what I understand you can run a full node and have other people lease their waves to you. I read on the site:"Leased proof-of-stake (LPoS) allows Waves holders to profit by using their balances to secure the network — whilst retaining full control of their funds."
I saw this interesting question on reddit which is related:
https://www.reddit.com/r/Wavesplatform/comments/92tbkp/wave_full_node/