"Coaching the All Blacks would be great but it's a tough gig to get and who knows how long Steve will hang around?" Rennie told Newstalk ZB.
"He's doing a great job and if they win another World Cup he may stick around longer.
"I've always talked about going overseas and having the chance to immerse ourselves in a different country. We'll see what happens beyond that. I only went to Manawatu for 18 weeks and ended up being there for six years, so who knows?"
Rennie has more immediate focuses before casting his attention too far in the future. He will want to finish his Chiefs tenure the way it began - with a Super Rugby title - and then establish a similar legacy in Scotland.
Given his credentials and intention to travel, Rennie would have been in hot demand among European clubs. He was reluctant to name names but said Glasgow's collective character and their lofty aims were what lured him.
"What I liked about Glasgow was they were really good people and I think they're really straight shooters," he said. "I like what they're trying to do - it's a really aspirational club." It's a club where Rennie will be dealing with a reduction in player depth, compared with the production line available to him in New Zealand, but he is confident he will be able to build a quality squad.
That may include enticing a few Kiwis to join him in the Pro 12 and having previously established a relationship with current Glasgow coach Gregor Townsend, who is set to replace Vern Cotter at Scotland, Rennie will look to sign some new recruits before he arrives.
He has in his contract the option of a third year with Glasgow, which is when decision time will arrive. But, before then, it will be the Chiefs who have to make up their minds on a replacement.
Ireland coach Joe Schmidt is heading home and looking for Super Rugby work, so will be considered a favourite. Current assistant Kieran Keane will surely be deserving of an elevation, while Cotter may complete the coaching merry-go-round and link up with the Chiefs.
"He's a very good man, Vern, and has a hell of a coaching pedigree," Rennie said. "If he decides to come home he'd be a strong candidate, no doubt."